Scent ID Dogs Found More Accurate in Scent Lineups of Women than of Men

Research in which I participated appears in the May 2012 issue of the Journal of Forensic Sciences. The lead researcher was Tadeusz Jezierski of the Polish Academy of Sciences, Department of Animal Behavior, who is a co-author of two chapters in Police and Military Dogs which deal with scent identification and scent lineups. I am constrained by contract from covering this development at the level I probably would had I not been a co-author, but a brief reference is appropriate. The research concluded that dogs in controlled trials more accurately distinguished the hand odors of women than the hand odors of men. If the target odor, the scent that the dog was supposed to match, was that of a man, the dogs were more likely to falsely alert to another man than was the case if the target odor was that of a woman. Also, in single-gender lineups, when all the odors were those of men or those of women, dogs were more likely to pick the correct woman than the correct man in a lineup. We note that the ability to identify individual women's hand odors better than men's may be due to gender differences in chemical compounds or due to a greater "attractiveness" of human female odors. As we discussed in Police and Military Dogs, scent identification of women is less common than that of men, but lawyers and expert witnesses in cases where the conduct of a scent lineup is in issue may find the research helpful in developing certain positions at trial or on appeal.

Jezierski, T., Sobczyńska, M., Walczak, M., Gorecka-Bruzda, M., and Ensminger, J. (2012). Do Trained Dogs Discriminate Individual body Odors of Women Better than Those of Men? Journal of Forensic Sciences, 57(3), 647-653, May 2012 (DOI: 10.1111/j.1556-4029.2011.02029.x).

K9 Fraud! Essential Reading for Handlers, Lawyers, and Judges

A book that should be in every police canine handler’s library, as well as the library of every lawyer and judge who handles cases involving canine evidence, is K9 Fraud! Fraudulent Handling of Police Search Dogs, by Resi Gerritsen and Ruud Haak (Detselig Enterprises Ltd., Calgary, Canada, 2010). The authors are married and live in the Czech Republic near the Austrian border, where they are training directors for the International Red Cross Federal, the UN, the International Rescue Dog Organisation, and the Fédération Cynologique Internationale.

Gerritsen and Haak are also the authors of K9 Professional Tracking: A Complete Manual for Theory and Training (Detselig, 2001). With Adee Schoon, Haak wrote K9 Suspect Discrimination: Training and Practicing Scent Identification Lineups (Detselig, 2002). Haak is the editor of Onze Hond, one of the widely circulated dog magazines in Europe. In the interest of full disclosure, my book on service and therapy dogs was mentioned favorably in Onze Hond.

The subtitle of K9 Fraud! is somewhat unfortunate in its reference to police search dogs, as this might suggest to American readers that the book is about search and rescue operations. Most of the chapters actually discuss fraud in scent identification lineups and in tracking and trailing. An entire chapter is devoted to canine responsiveness to human gestures, which any lawyer, or any judge, dealing with a cueing claim should read. The publisher did not serve this important work well in failing to provide an index, and I found it necessary to use post-its to highlight pages I will want to refer to again.

Those who have read other books by these authors, and authors with whom they have associated, will find some of the material familiar, if not on occasion repetitive. The difference is that where the other books (at least the ones with which I am familiar) look at canine practice from the perspective of how to do it right, this book focuses on how it can be done wrong. I am inclined to think that the latter approach may be more necessary for lawyers and judges, particularly in the U.S. As I pointed out in recent discussions of a drug bust and a station identification, many American judges are still inclined to accept the work of canine handlers uncritically and do not adequately consider what might have been done wrong. In all fairness, I must acknowledge that some courts, such as the Florida Supreme Court, have begun to look past the mystique and require a solid foundation for the admission of canine evidence.

Gerritsen and Haak are not afraid to take on handlers by name, some of whom are prominent and spoken of with respect. Of course, these authors are writing from and probably more influential in continental Europe than in the U.S.

A Botched Murder Prosecution Leads to Blanket Exclusion of Lineups in the Netherlands
 
A murder investigation and prosecution led to the exclusion as evidence of scent lineups performed in the North and East Netherlands over a period of nine years because it was found that a critical requirement for performing a scent lineup had been ignored by police during this period. The mistake was regarded as so critical that six police dog handlers were sentenced to prison for two years. One of the cases that led to this exclusion is discussed by Gerritsen & Haak in detail.

Jacqueline Wittenberg, a rich old widow living in the Dutch town of Deventer was murdered on September 23, 1999, but was not found for several days. There were no signs of a break-in. It was known that she did not admit strangers to her home, and only admitted people she knew if she expected them. The last one to call her on the night of the murder was Ernest Louwes, her tax advisor. Louwes claimed to have been far from Deventer at the time the call was made. A telecom expert testified, however, that if Louwes had made the call from anywhere but Deventer, the call would not have been relayed through the telecom antenna in Deventer.

A knife was discovered two days later under a neighbor’s porch. The neighbor who found it picked it up with his sleeve to avoid leaving his own fingerprints on it. The knife was used in a canine scent identification lineup, resulting in the identification of Louwes as having left scent on the knife. In 2002, the Supreme Court of the Netherlands concluded that the knife had not been the murder weapon. Louwes was released in 2003.

DNA extraction from the blouse that Wittenberg was wearing when she was murdered again pointed to Louwes, however, and he was resentenced in 2004 to 12 years in prison. Suspicions regarding Wittenberg’s handyman and his girlfriend began to surface, however, and additional investigation brought to light a number of discrepancies in their earlier stories. Louwes was again released in 2009. Dutch law still considers Louwes to be the murderer, but a number of observers now doubt his guilt.

The fact that Louwes was identified in a scent lineup where a knife that was later found not to have been used in the crime has apparently never been explained.

Prosecution of Dutch Police for Scent Lineup Failures 

The paragraph following the description of the Deventer case by Gerritsen and Haak says much about why scent lineups have come into question in Europe, despite being in general much more rigorously performed there than in the United States:

“The seven police dog handlers of North and East Netherlands region were prosecuted for perjury and forgery, because it was found that they hadn’t performed the scent identification line-ups exactly in accordance to the regulations. According to these rules, the dog handler may not know the position of the scent carriers of the suspect, to avoid influencing his dog. This step was found to be omitted in many cases between September 1997 and March 2006. Even worse, was that the official reports stated that all identification line-ups were processed in compliance with the standard codes of operation. In November 2007, the seven police dog handlers were convicted to penal labor of 240 hours. Six of the seven handlers were also incarcerated for two years and were removed entirely from their positions. Only the dog handler that had shed light on situation was allowed to continue his duty.”

Whether SWGDOG guidelines should be recognized as U.S. national standards involves issues of transparency and delegation of regulatory authority. Even if such issues were overcome and there were some general recognition of SWGDOG as establishing best practices applicable in a broad range of criminal investigative contexts, it is unlikely that the organization would ever be the beneficiary of criminal enforcement for failures to implement its recommendations.

A Tool for Judges and Lawyers

In researching Police and Military Dogs, I found that early decisions from the end of the 19th and the beginning of the 20th century had a better feel for what dogs could do than more recent cases. Many judges of those times—particularly judges in the American South, where tracking largely began as a police function—were hunters and experienced with the tracking of animals. More recent decisions, in contrast, often showed undue deference to the testimony of handlers, or, alternatively, regarded canine evidence as being produced by silly animals, hardly worthy of the court’s time, dogs of the sort the judges saw in the elevators of their high-rise condo buildings. For a brief time I wondered if I could create a taxonomy of pro-dog and anti-dog judges based on their tolerance for and appreciation of canine evidence, but no clear pattern of this sort emerged as I read over 1,200 judicial decisions. What did emerge was that many judges failed to recognize the slow but steady progress that was being made in the practical applications of canine olfaction, and the decisions often lacked any real understanding of how dogs behave or the limits of their skills. Appellate decisions often avoided careful analysis of trial court failures by labeling as harmless the errors that appeared to have been made.

Another circumstance I noted as I researched police canine law was an increase in claims of ineffective assistance of counsel being made by defendants convicted in significant part by canine evidence. No law school that I am aware of offers a class in this increasingly active area of criminal law. Reading through the lines of opinions, it was often apparent that defense counsel was quite effective in raising procedural issues and in offering stiff resistance to most evidentiary aspects of the prosecution’s case, but cross-examination of police dog handlers was often anemic and missed apparent weaknesses in their testimony. Defense experts were chosen for some general canine expertise, or for superior academic credentials, but were often not versed in the areas where the prosecution’s case might have been vulnerable to a countervailing perspective. Lines of questioning often bogged down on issues that did not bolster any viable defense position, while other aspects of a handler's testimony remained unaddressed.

I should say that this lack of adequate legal attention to canine evidentiary issues also comes from those, such as the Innocence Project, who want to have police dog work labeled as “junk science” and excluded altogether. Here the weaknesses of judges and lawyers are being distilled into a knee-jerk battle cry against the acceptance of canine evidence at all.

I recommend that all these participants in the criminal justice system read K9 Fraud! before writing another brief, opinion, or press release.

Thanks to L.E. Papet and Gail McConnell for suggestions that improved this blog.

Differences Between Tracking and Scent Lineups Are More Substantial Than Some Courts Recognize

A Texas court found that there is "little distinction between a scent lineup and a situation where a dog is required to track an individual’s scent over an area traversed by multiple persons.” Winston v. Texas, 78 S.W.3d 522 (Court of Appeals, 14th Dist., 2002). This supposed similarity, almost identity, of tracking and trailing to scent lineups, has been used by courts in applying the same foundational requirements to the admission of both types of evidence. There are, in fact, numerous differences between the two canine functions, and some are significant from a forensics perspective. The following list of differences is probably not exhaustive. Tracking and trailing descriptions are in Roman type, while scent lineup descriptions follow in italics.

1. Dogs trained to follow tracks or trails of targets usually on long, loose leads. Dogs trained in procedures designed to emphasize matching of scents correctly; dogs work either on lead or off lead in testing area.
2. Dogs may be trained in other police dog functions, or may be tracking specialists. Dogs may be trained in other police dog functions, but are generally specialists in European procedures and in the most reliable protocols.
3. Dog ideally scented to object touched by perpetrator but sometimes scented to area where perpetrator likely to have been present; dogs occasionally scented to pads. Dog scented to object likely to have scent of perpetrator or to scent pad created from object perpetrator may have touched.
4. Scent occasionally extracted and enhanced by scent transfer unit. Scent on scenting item and scents in stations of lineup frequently extracted and enhanced by scent transfer unit.
5. Dog more often following foot scent as individual human odor. Dog more often scented to objects touched by perpetrators’ hands but may be scented to item touched by another body part (e.g. elbow, face).
6. Scent source may have been touched by multiple individuals (“missing member” may be performed to eliminate non-suspects); track may have been crossed by multiple individuals. Scent source may have been touched by multiple individuals; lineup design generally precludes scents from individuals other than the suspect and foils in the lineup stations.
7. Dog must ignore cross tracks laid at different times generally by unknown individuals. Dog must choose between objects ideally scented at same time and by individuals of same gender, age, and ethnicity of suspect; objects are generally identical or alike.
8. Dog need not choose any individual but may lead to suspect. Dogs choose between a number of objects scented by target and decoys (in zero trials, no choice is correct).
9. Dogs may work in tandem or in groups. Dogs should always work alone; when trials involve using multiple dogs, equipment generally must be cleaned between each trial.
10. Object of work is to find path taken by perpetrator and find objects perpetrator may have left, and possibly find perpetrator. Object of trial is to determine if suspect was perpetrator.
11. Handler may have to know facts about perpetrator in case he encounters him or her while tracking (particularly if perpetrator may be armed and dangerous). Handler should be unaware of correct station and dog should not be able to see experimenter or other individual who knows correct station during trial.
12. Trail may be followed by more than one team at more than one time. Equipment must be cleaned between trials if dogs may have left saliva at scenting stations.
13. Trail cannot be followed after scent disappears. Test can be performed as long as scents are preserved.
14. Procedure may produce additional evidence (e.g., items dropped or abandoned by perpetrator, locations where perpetrator may have been). Procedure does not produce additional evidence.
15. Tracking occurs in diverse environments; dog may track to a building or vehicle, implicating privacy interests. Procedure generally conducted in police station or other facility.
16. Procedure rarely videotaped. Videotaping increasingly common and often required.
17. Tracking foundational requirements apply. Tracking foundational requirements require adaptation or ignoring (e.g. putting on track where perpetrator likely to have been; tracking continuously).
18. Cueing the dog generally only possible if suspect is encountered; dogs may sometimes be forced to follow a path against their inclination. Cueing the dog possible if the handler or other participant in the lineup visible to the dog knows the position of the suspect’s scent in the lineup.
19. Dog may have to be rescented if it loses trail or becomes distracted. In optimal protocols, dog will will not be rescented during trial.
20. Environment of tracking generally cannot be controlled beyond limiting interference of other investigators or bystanders. Environment should be highly controlled to avoid contamination and cueing.

I’ve discussed the distinctions between tracking and scent identification in a working paper posted on the Social Science Research Network (SSRN), Canine Tracking and Scent Identification: Factoring Science into the Threshold for Admissibility.

For a detailed discussion of the state of the law and research on scent lineups, see another working paper, Scent Identification in Criminal Investigations and Prosecutions: New Protocol Designs Improve Forensic Reliability, by Tadeusz Jezierski, Michael McCulloch, and me, also posted on SSRN.

The authors would appreciate comments on both of these papers. Please send comments on either paper to me at jensminger@msn.com.

Poorly Conducted Trailing and Scent Identification Procedures Lead to Wrongful Accusation

In a case arising in Texas in 2006, police, largely on the basis of evidence provided by a dog handler named Keith Pikett, concluded that Michael Buchanek had murdered Sally Blackwell. Several months after the investigation began another individual, Jeffrey Grimsinger, confessed to having killed Blackwell. Had it not been for this confession, the canine evidence provided by Pikett might have put Buchanek, who did a tour training Iraqi police, in prison. Grimsinger was suggested as a suspect early in the investigation but this seems to have been ignored by the officer in charge of the case, Sam Eyre.

Blackwell was abducted from her home on March 13. Her body was found two days later on March 15, 2006. Before the body was found, dogs and handlers from the Texas Department of Criminal Justice (TDCJ) had been brought to help search the area where Blackwell’s cell phone and purse were found. The dogs picked up no trail at the location and the handlers believed that the phone and purse had been thrown from a car. (The Texas Department of Criminal Justice has 47 kennels throughout its system, with 101 kennel staff (as of 2006). About half the kennels hold tracking dogs used primarily to track escaped convicts, but also to help law enforcement. There are also scent-specific canines that include drug detection dogs in the TDCJ system.)

The Police Department of Victoria, Texas, employed Keith Pikett, a handler of trailing and scent identification dogs, to help in the investigation. An affidavit sworn to by Eyre stated that Pikett’s dogs trailed from the place where Blackwell’s body was found to Buchanek’s home. This was false, as other evidence established that the dogs trailed to the home of the victim, and only after reaching Blackwell’s house was Pikett told that a “person of interest” lived at a different location. The dogs were then taken to a street near that location and re-scented, after which they went to Buchanek’s home. The dogs would have passed this house when they were trailing from Blackwell’s body to her home, but if they did so they did not alert at the time.

There was another problem with the tracking in that the investigators believed that Blackwell’s body had been taken to the place where it was found in a vehicle. Thus, trailing from the location where the body was found to either house would have involved dog’s following a body in a car. Pikett argued that this was in fact possible, but the TDCJ handlers doubted it could be done. Some of those handlers, according to Buchanek’s complaint, expressed the belief that Pikett was “full of b.s.” The federal district court observed that the route followed by the dogs from the location of the body to the victim’s home would have required trailing the car transporting the body over five miles.

Pikett cited a piece in the FBI’s Forensic Science Communications noting that ventilation systems in cars move fresh air through the interior of a vehicle and into the external atmosphere, conceivably laying a scent trail a dog could follow. (Stockham, R.A., Slavin, D.L., and Kift, W. Specialized Use of Human Scent in Criminal Investigations. Forensic Science Communications, July 2004, vol. 6(3)). Research might support this possibility for short distances, but the five miles involved in this case and several major highways would truly be exceptional.

When Pikett and his dogs arrived in the vicinity of Buchanek’s home (after the dogs supposedly trailed to Blackwell’s home), an officer asked a man walking his dogs to remove them from the street because police dogs were coming. The court said this may have indicated that Pikett expected his dogs to trail to Buchanek’s house. The court also noted that the officer was preceding the dogs and it may have been his scent they were following. Even worse, it may have meant that Pikett was leading his dogs, rather than the other way around.

Pikett also conducted a scent lineup. The scent for Buchanek used in the lineup appears to have been a legal document Buchanek may not have touched for two years and may have been more recently handled by law enforcement officers. The other scents in the lineup may have come from “filler scents” that Pikett kept for such purposes, though this was not definitely established. (Another case involving Pikett’s services describes Pikett testifying that he has “a large selection of scent samples” for scent lineups, and that he has separated his samples by race and gender. Winfrey v. State, 2009 WL 1636849 (2009).) If filler samples were used here, the scents were not prepared in the same way or at the same time, which would be a serious defect in a scent lineup. There was also no evidence as to whether the dogs were on leads or not, or as to how Pikett was kept blind as to the placement of the suspect’s scent (if he was indeed blind). The lineup was performed in a police department parking lot. Officers who re-arranged the bags containing the scents in a row of cans may have touched the bags in this process, creating the possibility, if not the likelihood, of contamination. There were probably other problems with the scent lineup but there is no detailed description of how it was conducted.

In the two decisions of the federal district court, motions for summary judgment have been denied, clearing the way for a trial. Buchanek v. City of Victoria, 2009 WL 500564, 2010 WL 1268069 (S.D. Tex 2010). The case has received national attention when the first decision was released. John Schwartz, “Picked From a Lineup, on a Whiff of Evidence,” New York Times, November 11, 2009, p. 1.

Scent lineups have come to be called “junk science” by those who believe that wrongful convictions as a result of these lineups are all too common. This case may be unique in that a single handler may have turned trailing as well as scent identification into “junk science” in a single investigation.

Addendum. Winfrey has been reversed by the Texas Court of Criminal Appeals. This court noted that no eyewitnesses put the defendant at the crime scene, the state was unable to match the defendant to a fingerprint and footprints found at the crime scene, and the defendant did not match the DNA profile obtained from the crime scene. The evidence convicting Winfrey consisted of his belief that he was the number one suspect when he wasn't and the fact he told a cellmate things he had heard about the crime but said nothing about his own involvement to the cellmate. The court found this "legally insufficient to support a conviction of murder beyond a reasonable doubt." The court cited other state courts that had held that dog-scent evidence was insufficient, standing alone, to support a conviction, and cited Taslitz (42 Hastings Law Journal 15 (1990)) in holding that scent-discrimination lineups were to be regarded as "separate and distinct from dog-scent tracking evidence." The court said that the scent lineup evidence could raise a "strong suspicion" of the defendant's guilt but could not convict him. A judgment of acquittal was entered by the appellate court. Winfrey v. Texas, 2010 WL 3656064 (Tex. Crim. App. 2010). Thanks to Gail Kikawa McConnell of the Fort Bend County, Texas, District Attorney's office for emailing me about the reversal.