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Criminal investigations and polygraph examinations
This paper explores the relationship between criminal investigations and polygraph examinations. For law enforcement agencies, specifically, the polygraph provides a vital tool in investigations. Various lie detectors have been in use by officers since the early twentieth century and as the technology behind the devices evolves so do the various practical applications within the field of law enforcement. In this paper, an in depth look is taken at interview and interrogation techniques, the Constitutional rights of the suspects, and the uses of polygraph testing.
Criminal Investigations and the Polygraph
What are criminal investigations? Basically criminal investigations are an examination of the facts, circumstances and situations related to the incident for the sole purpose of rendering a conclusion to the case. This could be by clearing a subject of any wrong doing or prosecuting them to the fullest extent of the law. Criminal investigators are law enforcement professionals who work to solve crimes or uncover information about a crime. While conducting the investigation, an investigator closely scrutinizes and analyzes information received from many different sources and must therefore be able to systematically separate that information that is considered reliable from that which is considered unreliable information. An investigator must be able to distinguish between fact and fiction.
Law enforcement in general is charged with the responsibility of preventing criminal acts, but often we as law enforcement are reactive instead of proactive. This is in large part due to many law enforcement agencies being undermanned, overworked and underpaid.
Criminal Investigations is an art and science. What makes a good criminal investigator? More and more agencies are requiring their investigators to have an Associates or Bachelor’s degrees. In the 22 years I have been a law enforcement officer, I have had people work with me that have had Associates, Bachelors and even a few Masters Degrees. I have said many times that I would rather have someone with a high school education, good common sense, uses good judgment, and has several years of experience on the street than to have someone with a PhD and no common sense. A college degree does not necessarily make a good law enforcement officer. A good investigator needs to be self motivated and not someone that has to be constantly having someone looking over their shoulder.
The good investigator will know how to speak to people of all walks of life. Often times, we are dealing with people that come from homes where drugs, alcohol, poverty and abuse are common place in their life. Some have little or no respect for law enforcement so we must be able to speak to them and make them understand that we are there to get to the bottom of a situation, while still trying to earn their respect.
While good investigative work will not significantly reduce crime by itself, the investigation of any crime places significant responsibilities upon the investigator. Successful investigators must possess essential qualities such as good communications skills, strong ethics, initiative, resourcefulness and compassion. Moreover, investigators have a responsibility to ensure that crimes are investigated effectively and thoroughly.
Investigating criminal offenses is one the most important aspects of law enforcement. Once
a crime is reported to the police, investigators have several responsibilities to work towards
solving the crime. This includes gathering documents, evidence and information from various
sources. For the most part, the roots of criminal investigation can be traced back to England in
the eighteenth-century, a time period marked by numerous social, political and economic
changes. These changes were catalysts in the creation of the first modem detective force, the
Bow Street Runners. In addition, London was the home of the first police reformer, Robert Peel.
Both of these contributions later became important in the development of police organizations
and criminal investigation in the United States.
Within the criminal investigation process, investigators frequently use various scientific methods found in criminalistics to help identify suspects, evidence, and collect information; all of which is used to convict criminal offenders. Criminalistics draws from diverse disciplines such as geology, physics, chemistry, biology and mathematics, to study physical evidence related to crime.
Investigators will sometimes need to verify information of victim’s, witnesses and statements from suspects in crimes. When this occurs we often turn to other means of interview and interrogations and seek the assistance of either Polygraph operators or Computerized Voice Stress Analyzers.
Since the Computerized Voice Stress Analyzer is relatively new and the time it takes to complete a test is only about thirty minutes, many officers have come to depend upon it, due to time constraints. However, most have determined that for the more serious crimes, the best results still come from a polygraph.
Over the years, I have seen the use of the polygraph solve numerous cases. From property crimes to homicides, the polygraph has become an invaluable instrument for not just my agency, but law enforcement agencies throughout the world.
Since the beginning of time man has sought to verify the truth and detect deception by
various means including torture and trial by ordeal, which still persist in many civilized
as well as underdeveloped countries. (Matte, 2002, pg 11)
Cesare Lombroso (an Italian Criminologist) 1895, was one of the first to use blood pressure-pulse tests on actual criminal suspects while assisting police in the identification of criminals. After making a modification to the plythysmograph, he would place the suspect’s fist in a water filled tank. The suspect’s fist was sealed using a rubber membrane across the top of the tank.
The suspects pulsations of blood in the fist were transferred to the water and the changes in water level were carried over into an air filled tube, which in turn recorded the pulsations on the revolving smoked drum. (Matte, 1996, p. 13)
In 1907, S. Veraguth described his observations of the galvanic phenomena and emotions. He is believed to be the first to use the term “psychogalvanic reflex." Veraguth believed the electrical phenomena was attributable not to the vascular changes in the skin, but to activity in the sweat glands. (Matte, 1996, p. 15 – 16)
In 1915, Dr. William Marston devised the systolic blood pressure deception test. It measured intermittent recordings of a person’s systolic blood pressure using a stethoscope and a medical blood pressure cuff. This was also referred to as the “Discontinuous Technique."
In 1921, John Larson, who worked for the Berkley California Police Department, developed an instrument that continually and simultaneously measured respiration and cardiovascular changes.
In 1925, Leonarde Keeler (a Stanford University psychology major who had gained firsthand experience in polygraph interrogations from Larson at the Berkeley Police Department) developed an improvement of Larson's apparatus. Keeler's instrument, like Larson’s, recorded relative changes in blood pressure, pulse rate, and respiration patterns.
However, Keeler developed a metal bellows, also known as a tambour, which was connected by mechanical actuating devices to small fountain pens. Volume changes within a blood pressure arm cuff and an accordion type tube also known as a pneumograph tube circling the chest or stomach of the subject were transferred in heavy walled rubber tubes to the aforementioned tambours. Keeler further designed a kymograph that pulled, at a constant speed, chart paper under the recording pens from a roll of chart paper located inside the instrument.
In 1938 Keeler included a third physiological measuring component in his instrument,
the Psychogalvanometer (PGR) also known as the galvanic skin reflex (GSR). The PGR
reflected emotional changes by measuring changes in a person’s skin resistance to electricity.
This was accomplished by transmitting a constant minute electrical current through the skin of a
selected fingertip. (Matte, 1996, p.25)
There have been numerous improvements to the modern day polygraph. In 1974, the
Stoelting Company produced the first electronic instrument. LaFayette Instrument Company
followed several years later with an instrument that was partly mechanical and electronic. Since
then, other companies have come out with computerized versions of the polygraph.
Today’s modern polygraph measure’s respiratory, Galvanic skin response, and blood-
pressure and pulse rate. Most polygrapher’s use a computerized instrument today.
There are still those that believe that the analog system is still superior because computer’s just
can’t be trusted.
The use of the polygraph is worldwide. Almost every law enforcement agency in the United States and many overseas agencies either use the polygraph for pre-employment purposes or for criminal investigations.
The use of the polygraph for pre-employment in law enforcement has been in use since the 1950’s. Polygraph testing is currently being used in more than 50 countries in the fields of corrections, criminal investigations, intelligence/counter intelligence and civil matters. In the United States alone all federal law enforcement agencies either employ their own polygraph examiners or use the services of examiners employed in other agencies. Examiners and quality control programs exist in the FBI, US. Secret Service, US Army CID, US Marine Corps CID, Air Force OSI, Navy NCIS, US Customs, US Marshals, Defense Criminal Investigation Service, Internal Revenue Service, US Capitol Police, Food & Drug Administration, Department of Energy, Central Intelligence Agency, Police & County Sheriff’s departments, sex therapists and numerous other investigative bodies. (Asperen)
All federal law enforcement agencies require prospective employee’s to submit to and pass a polygraph before being hired. Polygraphs are being used by the CIA and military in Iraq, Afghanistan and Guantanamo Bay, Cuba for interrogating suspected terrorists and enemy combatants.
The use of polygraphs in law enforcement has not always been met with open arms. It has come under fire numerous time’s in the courtroom. One of the first and most significant cases set the standard for the use of polygraphs in 1923. FRYE v.UNITED STATES. 293 F. 1013(D.C. Cir 1923). This was a federal case decided by the District of Columbia Circuit. In this case, Van Orsdel, Associate Justice, wrote the opinion for the court. It stated:
Appellant, defendant below, was convicted of the crime of murder in the second degree, and from the judgment prosecutes this appeal. A single assignment of error is presented for our consideration. In the course of the trial, counsel for the defendant offered an expert witness to testify to the result of a deception test made of the defendant. The test is described as the systolic blood pressure deception test. It is asserted that blood pressure is influenced by changes in the emotions of the witness, and that the systolic blood pressure rises are brought about by nervous impulses sent to the sympathetic branch of the autonomic nervous system. Scientific experiments, it is claimed, have demonstrated that fear, rage, and pain always produce a rise of systolic blood pressure, and that conscious deception or falsehood, concealment of facts, or guilt of crime, accompanied by fear of detection when the person is under examination, raises the systolic blood pressure in a curve, which corresponds exactly to the struggle going on in the subject's mind, between fear and attempted control of that fear, as the examination touches the vital points in respect of which he is attempting to deceive the examiner. In other words, the theory seems to be that truth is spontaneous, and comes without conscious effort, while the utterance of a falsehood requires a conscious effort, which is reflected in the blood pressure. The rise thus produced is easily detected and distinguished from the rise produced by mere fear of the examination itself. In the former instance, the pressure rises higher than in the latter, and is more pronounced as the examination proceeds, while in the latter case, if the subject is telling the truth, the pressure registers highest at the beginning of the examination, and gradually diminishes as the examination proceeds. Prior to the trial defendant was subjected to this deception test, and counsel offered the scientist who conducted the test as an expert to testify to the results obtained. The offer was objected to by counsel for the government, and the court sustained the objection. Counsel for defendant then offered to have the proffered witness conduct a test in the presence of the jury. This also was denied. Counsel for defendant, in their able presentation of the novel question involved, correctly state in their brief that no cases directly in point have been found. The broad ground, however, upon which they plant their case, is succinctly stated in their brief as follows: 'The rule is that the opinions of experts or skilled witnesses are admissible in evidence in those cases in which the matter of inquiry is such that inexperienced persons are unlikely to prove capable of forming a correct judgment upon it, for the reason that the subject matter so far partakes of a science, art, or trade as to require a previous habit or experience or study in it, in order to acquire a knowledge of it. When the question involved does not lie within the range of common experience or common knowledge, but requires special experience or special knowledge, then the opinions of witnesses skilled in that particular science, art, or trade to which the question relates are admissible in evidence. Numerous cases are cited in support of this rule. Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs. We think the systolic blood pressure deception test has not yet gained such standing and scientific recognition among physiological and psychological authorities as would justify the courts in admitting expert testimony deduced from the discovery, development, and experiments thus far made. The judgment is affirmed. (Frye v. United States, 293 F. 1013 D.C. Cir. 1923)
The Court in Frye held that expert testimony must be based on scientific methods that are sufficiently established and accepted. The D.C. Circuit held that evidence could be admitted in court only if "the thing from which the deduction is made" is "sufficiently established to have gained general acceptance in the particular field in which it belongs." Frye dealt with a systolic blood pressure deception test, a "crude precursor" to the polygraph. In 1923, this blood pressure test was not widely accepted among scientists, and so the Frye court ruled it could not be used in court. Over the years, scholars disputed the proper scope and application of the Frye test.
This ruling, known as the Frye Standard stood until 1993 when another Federal case superseded it. In Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993), the United States Supreme Court determined the standard for admitting expert testimony in Federal cases.
The facts of the case are as follows:
Jason Daubert and Eric Schuller had been born with serious birth defects. They and their parents sued Merrell Dow Pharmaceuticals Inc., a subsidiary of Dow Chemical Company, in a California state court, claiming that the drug Bendectin had caused the birth defects. Merrell Dow removed the case to federal court, and then moved for summary judgment because their expert submitted documents showing that no published scientific study demonstrated a link between Bendectin and birth defects. Daubert and Schuller submitted expert evidence of their own that suggested that Bendectin could cause birth defects. Daubert and Schuller's evidence, however, was based on in vitro and in vivo animal studies, pharmacological studies, and reanalysis of other published studies, and these methodologies had not yet gained acceptance within the general scientific community.
The district court granted summary judgment for Merrell Dow, and Daubert and Schuller appealed to the Ninth Circuit. The Ninth Circuit found the district court correctly granted summary judgment because the plaintiffs' proffered evidence had not yet been accepted as a reliable technique by scientists who had had an opportunity to scrutinize and verify the methods used by those scientists. Furthermore, the Ninth Circuit was skeptical of the fact that the plaintiffs' evidence appeared to be generated in preparation for litigation. Without their proffered evidence, the Ninth Circuit doubted that the plaintiffs could prove at a trial that the Bendectin had, in fact, caused the birth defects about which they were complaining. The plaintiffs asked the Supreme Court to review the Ninth Circuit's decision, and it agreed to do so.
The plaintiffs argued that after Congress adopted the Federal Rules of Evidence in 1975, Frye was no longer the governing standard for admitting scientific evidence in trials held in federal court. The Supreme Court agreed. It had already ruled that where common-law rules conflicted with provisions of the Rules, the enactment of the Rules had the effect of supplanting the common law. Frye was certainly part of the federal common law of evidence because it was decided almost 50 years before the Rules were enacted. But the text of the Rules did not suggest that Congress intended to keep the Frye rule, and so the Court reasoned that Frye was no longer the rule. (Daubert v Merrell Dow Pharmaceuticals)
The Court defined "scientific methodology" as the process of formulating hypotheses and
then conducting experiments to prove or falsify the hypothesis, and provided a nondispositive,
nonexclusive, "flexible" test for establishing its "validity":
Empirical testing: the theory or technique must be falsifiable, refutable, and testable.
Subjected to peer review and publication.
Known or potential error rate.
The existence and maintenance of standards and controls concerning its operation.
Degree to which the theory and technique is generally accepted by a relevant scientific community.
This basically states that the judge is given the task of "gatekeeping", or assuring that scientific expert testimony truly proceeds from "scientific knowledge".
There have been cases that have allowed polygraph evidence to be submitted in court. In a 2007 case from Summit County, Ohio, Shahil Sharma was charged with Sexual Battery. He claimed the sexual contact was consensual. His attorney asked the judge to either throw out the case or allow evidence that the defendant had taken and passed a polygraph. The judge would not throw the case out but did allow testimony that the defendant had taken and passed a polygraph to be submitted as evidence. The prosecutor fought the decision and stated they (State) would appeal the decision. The defendant’s attorney stated that the prosecutor uses polygraphs to weed out bad cases before indictment.
They prosecutor in the case states that polygraphs are normally not accepted in sexual assault cases because the defendant honestly believes that consent was given, they could possibly give a truthful answer to a question of that type.
Ohio law allows for polygraphs to be used if both sides agree to the outcome prior to the examination being administered. This is referred to as a stipulated polygraph, and it’s the only way a polygraph can be submitted as evidence in a case.
Shalil Sharma was found not guilty of the charges in 2007. The judge stated her opinion was not based solely on the outcome of the polygraph, but deductive reasoning and common sense. This case may have set new precedence for use of polygraph evidence in the court.
The use of polygraphs in specific types of criminal cases has been questioned for a number of years. As investigator’s, we sometimes have the need to verify a victim’s statements particularly in sexual assault cases, where often times a suspect in a case may claim that the sexual contact between he and the victim was consensual. In those instances an investigator would normally interview all parties involved thoroughly. After interviewing and getting all the facts of the case, he would have all the parties involved write detailed statements. Sometimes, the written statements don’t match up with what was given in the verbal statements.
When a case of sexual assault become’s a he said/she said case an investigator will ask one or both parties to submit to a polygraph or other “lie detector". This practice has come under scrutiny by many states in the past few years and therefore many states have passed laws prohibiting sexual assault victims from being required to submit to polygraphs or other lie detectors.
Here are just a few examples of various state laws:
North Carolina (N. C. Gen. Stat. § 15A-831.1)
Criminal and juvenile justice agencies in North Carolina are barred from requiring victims or witnesses of sexual offenses to undergo examination using a polygraph or other truth-telling device as a condition of proceeding with case investigation. If an agency wants to administer such an examination, they must inform the person to be tested that the examination is voluntary, that the results of the examination are not admissible in court, and that taking or refusing the examination will not be the sole factor affecting whether the case is investigated or not. If the person refuses the examination and the agency decides not to pursue the investigation, the agency (upon request) must provide the person a written list of the reasons why the agency made this decision.
Virginia (Va. Code § 19.2-9.1)
Law enforcement officers, district attorneys, and other government officials in Virginia are barred from asking or requiring victims of sexual offenses to undergo examination using a polygraph or other truth-telling devices as a condition of proceeding with case investigation, charging, or prosecution. If an official wishes to administer such a test, the official must inform the victim that the test is voluntary, the results are not admissible as evidence in court, and that the case will not be continued solely because the victim decides to submit to the examination.
In instances where one takes the polygraph and the other doesn’t, it still does not give the investigator probable cause to arrest or close the case. The polygraph is no more than a tool to an investigator and without good interview and interrogation skills; it’s no more than a computer sitting on a desk, a magic eight ball, or a flip of a coin.
The polygrapher’s interview and interrogation skills will come into play when you have a person who is not forthcoming with all the information or knowledge that they have of the situation at hand. There are normally three different types of people that an investigator will be conducting interviews with:
What are interviews and interrogations and how do they differentiate?
Interviews and interrogations are often used interchangeably among law enforcement officers, yet there is a significant difference between the two. An interview is non-accusatory and is used when an investigator has reason to believe that a subject is involved, or might have knowledge of a crime. It is used to gather information on both the crime and the subject being interviewed. An investigator should never pass up a chance to speak with a subject; you may only have one opportunity. (Buckley, 2004, p 5)
Investigators should remember three points:
Many criminal cases, even when investigated by the best investigators are capable of solution only by means of an admission or confession from the guilty subject or upon basis of information obtained from the questioning of other criminal suspects.
Criminals, except those caught in the commission of their crimes, ordinarily will not admit their guilt unless questioned under conditions of privacy for perhaps several hours.
In dealing with suspects in criminal cases, the investigator must of necessity employ less than refined techniques that are considered appropriate for everyday affairs between law abiding citizens. (Buckley, 2004)
The interview can be conducted in the early stages of the investigation. You may not have all the information about the case or analyzed all the evidence before conducting the interview, but the purpose of the interview is to obtain information.
The interview can be conducted anywhere practicable. Ideally the perfect environment would be a room specifically designed for that purpose, but for all reasonable purposes it can be conducted anywhere. It’s sometime necessary to conduct interview’s in the field, whether it’s in a person’s home, office or patrol car. (Buckley, 2004, p.6)
The interview is free flowing and unstructured. The investigator should always be willing to explore different avenues of communication. You can’t say, “This is the way I do my interviews, and I’m not willing to change." The good investigator has to remain flexible.
An interrogation is accusatory. The person is normally in custody and not free to leave. Deceptive subjects are not likely to offer admissions against self incrimination until they are convinced the investigator is certain of their guilt. The interrogation involves active persuasion. The investigator is interrogating either because the subject was being deceptive during an interview or polygraph. The investigator will use tactics that make statements rather than ask questions. (Buckley, 2004, p.7)
Interrogation is fundamentally defined as a method for interviewing a source to obtain information that the source would not otherwise willingly disclose. A typical purpose is not to force a confession, but rather to develop sufficient rapport, playing on the source's character, to prompt the source to disclose their information. Thus, the fundamental concept of interrogation does not entail torture nor does it involve a complex "movie" persona of intimidation and violence. Rather, many times interrogation is building a connection and a trust with the subject so that the source will ultimately reveal information that he or she was formally unwilling to reveal. (Buckley, 2004)
The purpose of the interrogation is to learn the truth. The end result will not always come in a confession. Sometime’s innocent people are interrogated and their innocence becomes apparent only after being accused of the crime. An interrogation can be considered successful if the truth is learned.
An interrogation is conducted in a controlled environment. Often the subject being interrogated is in custody and therefore is not free to leave. Because persuasive tactics are used the environment needs to be private and free of distractions. Determining the type of case being investigated, interrogations should be recorded using both audio and video when possible. Some states require that all interviews/interrogations be recorded in capital cases. (Buckley, 2004, p.8)
In the absence of confessional or other corroborative evidence problems exist in determining whether an individual is telling the truth, or has any knowledge relating to a specific issue or offense. A number of homicides, rapes, abductions, extortions and other serious crimes remain unsolved due to a lack of substantive or verifiable leads.
If all other leads have been exhausted and an investigator believes the subject may still be withholding information or the need is to verify information, the investigator will then turn to the polygrapher. The polygrapher is normally an experienced investigator with above average interview an interrogation skills.
The polygraph test is one of the most controversial criminal investigative techniques of all-time. From the initial years of the invention to today, there is not a consensus about the investigative tool. That is why there are many people for and against the administration of polygraph tests.
A polygraph is an instrument that records certain physiological changes in a person undergoing questioning in an effort to obtain truth or deception. A polygraph simultaneously records a minimum of respiratory activity, galvanic skin resistance/conductivity and cardiovascular activity.
Polygraphy, or psychophysiological detection of deception, is based upon a scientific theory that can be tested with the methods of science. Any conscious effort at deception by a rational individual causes involuntary and uncontrollable physiological responses which include measurable reactions in blood pressure, peripheral pulse-amplitude, breathing and electrodermal response. The most commonly used techniques for the psychophysiological detection of deception are control/comparison question tests. The control question test (CQT) assesses a person’s credibility by looking for a differential reaction between two questions: the relevant and comparison questions. It has been shown that a person will develop a "psychological set" and direct their attention to the question that poses the greatest anxiety, concern or threat to his/her well being. (Aperen)
Law enforcement agencies using the polygraph do so on the basis that it is an important investigative aid, but not a substitute for good investigative techniques. For decades the law enforcement community has used polygraph testing as an investigative aid to: verify the statements of victims; establish the credibility of witnesses; evaluate the truthfulness of suspects and to help exonerate the innocent. (Aperen)
The polygraph is and can only be a voluntary process. All investigators and law enforcement in general should be familiar with Miranda vs. Arizona. This case protects a person’s Fifth and Sixth Amendment Rights. This was a landmark case where the United States Supreme Court ruled that both inculpatory and exculpatory statements made in response to interrogation by a defendant in police custody will be admissible at trial only if the prosecution can show that the defendant was informed of the right to consult with an attorney before and during questioning and of the right against self-incrimination prior to questioning by police, and that the defendant not only understood these rights, but voluntarily waived them.
The person in custody must, prior to interrogation, be clearly informed that he has the right to remain silent, and that anything he says will be used against him in court; he must be clearly informed that he has the right to consult with a lawyer and to have the lawyer with him during interrogation, and that, if he is indigent, a lawyer will be appointed to represent him.
The court also made clear that if the individual chose to exercise those rights, if the individual indicates in any manner, at any time prior to or during questioning, that he wishes to remain silent, the interrogation must cease. If the individual states that he wants an attorney, the interrogation must cease until an attorney is present. At that time, the individual must have an opportunity to confer with the attorney and to have him present during any subsequent questioning.
The individual may waive these rights. It is always a good practice to read the individual his rights and have him acknowledge in writing that he understands these rights, and that he wishes to speak with you without having an attorney present. Also have the individual sign the acknowledgement.
In today’s society with the ever increasing crime rate, law enforcement officers need all the help they can get. There have been numerous scientific breakthroughs in the past 20 years. Crime Laboratories have made great advances in DNA technology, ballistics, and fingerprinting. There have also been many advances in Psychophysiological Detection of Deception using polygraphs. However, nothing will ever replace the skills of an investigator who possesses good interrogation techniques that can speak to people.
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