EvidenceProf Blog

Editor: Colin Miller
Univ. of South Carolina School of Law

Friday, June 10, 2011

Dog Day Afternoon: Casey Anthony Trial Raises Questions About Cadaver Dogs

With the Casey Anthony trial, most of America is becoming acquainted for the first time with the "cadaver dog." Here is an excerpt from a CNN article about the cadaver dog's role in the investigation of the death of Caylee Anthony:

A dog trained to locate human remains alerted his handler to them in two locations: the trunk of Casey Anthony's car and a corner of her parents' back yard, the handler testified in Anthony's capital murder trial Tuesday.

On first pass by the dog, Gerus, around Anthony's white Pontiac Sunfire on July 17, 2008, "he started indicating in the rear of the vehicle," said Orange County, Florida, sheriff's Deputy Jason Forgery, a K-9 handler. "I could tell he was working something."

As the dog came around the front of the car, Forgery said he asked that the trunk be opened. When Gerus came around to the trunk, he put his front paws inside, then lay down -- a signal to Forgery that he had detected the scent of remains.

He said Gerus also alerted in the southeast corner of the Anthony back yard. However, during a cross-examination that grew testy at times, Forgery told defense attorney Jose Baez that after technicians had examined the area and scraped the surface of the land, he returned the following day and the dog did not alert in the back yard.

And here is a video clip of some of Forgery's testimony, including an interesting cross-examination by defense counsel regarding the (in)accuracy of cadaver dogs:

I think that most people have more familiarity with drug-sniffing dogs, dogs who track a suspect from a crime scene, and scent-lineup dogs, which are

exposed to the scent from items found at crime scene, and are then walked by a series of containers with samples swabbed from a suspect and from others not involved in the crime. If the dog finds a can with a matching scent, it signals — stiffening, barking or giving some other alert its handler recognizes.

In this post, I have two goals: (1) comparing the qualification of these latter two types of dogs and cadaver dogs for expert testimony purposes; and (2) considering whether dog "searches" should be allowed without warrants under the Fourth Amendment given yesterday's post.

Go to the Dogs

In addressing this first question, let's consider the opinion of the Court of Appeals of Texas, Houston, in Trejos v. State, 243 S.W.3d 30 (Tex.App.-Houston [1 Dist.] 2007). Trejos is at least somewhat similar to the Casey Anthony case. Frank Trejos and his wife lived with Maria Barrientos, his mother-in-law. Four days after Maria was last seen, Trejos reported to the police that she was missing, but neither he nor his wife helped Maria's friends post missing persons fliers, nor did they make any other attempts to find her.


the Houston Police Department Crime Laboratory processed Maria's house. Testing revealed a "presumptive test for blood" on adult footprints in the kitchen and the hallway and on a towel in the bathroom. The towel was sent to the Department of Public Safety ("DPS") for follow-up testing, but the test showed that there was no "apparent blood." The following day, Maria's car, with the keys still in the ignition, was found abandoned less than two miles from her ex-husband's house. Maria's purse was in the car. A presumptive test showed the presence of possible blood on the floormats in the back floorboard of the car

Trejos, however, denied any involvement is Maria's disappearance, and the case went dormant for seven years. After seven years, Trejos was interrogated again, and he made a "confession." Specifically, he

said that he was angry with Maria for nagging him. When she "came up in [his] face" he struck her with his fist. She fell to the kitchen floor. Maria was bleeding and "freaking out," so [Trejos] choked her. After Maria was dead, [Trejos] and his wife took her to the bathroom and placed her in the tub. [Trejos]'s wife cut Maria's wrists to try to make it look like she committed suicide, but the wounds did not bleed. [Trejos] and his wife put Maria's body in the trunk of their car and dumped her body in a ditch.

Police officers then

took two dogs trained to detect the scent of cadavers to the location where [Trejos] said that he and his wife had dumped Maria's body. The two cadaver dogs and their handlers worked the area independently of one another so that they would not influence each other. Both dogs alerted within five or six feet of one another, at the spot that [Trejos] had indicated he had placed the body. Although an excavation was performed, no remains were found.

At his murder trial, Trejos moved to suppress his confession and preclude admission of evidence relating to the cadaver dogs, but he was unsuccessful on both points and in his defense overall. He thereafter appealed, claiming, inter alia, that the cadaver dogs were not sufficiently qualified to allow for expert testimony regarding their alerts. In response, the Court of Appeals of Texas noted that

In determining whether a dog used in a scent lineup was qualified, we have applied five factors....In Risher, we held that a scent-lineup dog is qualified if "it (1) is of a breed characterized by acuteness of scent and power of discrimination, (2) has been trained to discriminate between human beings by their scent, (3) has been found by experience to be reliable, (4) was given a scent known to be that of the alleged participant of the crime, and (5) was given the scent within the period of its efficiency."... The Fourteenth Court of Appeals applied these same five factors in Winston to determine the reliability of a dog that tracked a burglary suspect based on human scent left at the crime scene.

The court then, however, concluded that

Searches by cadaver dogs are different from searches by dogs for scents left by live humans. Deputy Pikett testified that cadaver searching is a less rigorous skill because it only requires the dog to be able to distinguish between human scents and animal scents, and the dog need not further distinguish between individual humans. As we explain below, because the skills necessary for a cadaver dog differs from the skills necessary for scent lineups or the tracking of suspects, we conclude that only some of the five factors in Risher apply to searches by cadaver dogs.

Obviously, the fourth factor is irrelevant because a cadaver dog does not search for the scent of any specific person, and the court also found that the fifth factor is irrelevant "because the immediacy of the search is not indicative of the efficiency of the scent." So, how about the first three factors? With regard to the first factor, the court held that

Deputy Pikett testified that all dogs have a more acute sense of smell than humans and that bloodhounds have an olfactory sense that is 26 times that of a human. Deputy Pikett explained that because a cadaver dog need not distinguish between the scents of different individuals and need only distinguish between the scent of human and animal remains, a breed such as a bloodhound that is traditionally known for its acuteness of scent is not necessary to use as a cadaver dog. Deputy Pikett further explained that a bloodhound is typically not a good cadaver search dog because bloodhounds are “not great obedience dogs” and typically must be worked on a lead, or leash. Deputy Pikett testified that in a large area search, a dog that can work off-lead is more credible because it is free to make an independent find, without the possibility that its handler will lead it to a particular area. Deputy Pikett said that other breeds, "such as Rottweilers mixed-breeds, Lab[radors] and so forth" can perform as cadaver dogs. We conclude that the breed of dog characterized by acuteness of scent is not determinative of a cadaver dog's qualification. However, we slightly modify this factor to examine whether the dog type or breed typically works well off-lead.

For the second factor, the court concluded that

Cadaver dogs are not trained to discriminate between human beings based on scent because the identity of the body being searched for is generally not in dispute. Deputy Pikett explained that the important distinction for a cadaver dog to master is between human remains and animal remains. The training begins with fairly fresh cadaver scent in a relatively easy location. The dogs progress to older body scents and then to the introduction of foreign scent distractions such as deer, horse, or cow bones. We conclude that this requirement must be adapted slightly for determination of the reliability of cadaver dogs by examining whether the dog has been trained to discriminate between human cadaver scents and animal scents.

And, in connection with the third factor, the court determined that

Proven reliability must be a qualifying characteristic of a cadaver dog, just like the need for proven reliability of dogs used in scent-lineups and the tracking of suspects. Deputy Pikett testified that a dog that cannot pass the training tests—for example, by failing to distinguish human and animal remains—will be retired from cadaver search work. To ensure that the dog can distinguish human and animal scents, Deputy Pikett explained that a dog in training must first prove that it can actually find a human scent, and then the training progresses to older scents, followed by the introduction of foreign scents. We therefore conclude that this factor is applicable to the qualifications and reliability of a cadaver dog.

In reviewing (relatively scarce) precedent from across the country, it seems like the Trejos opinion is not an anomaly; instead, courts use pretty lax standards in determining whether cadaver dogs are qualified.

Search Me

In light of yesterday's post, I want to address a second aspect of cadaver dogs, drug-sniffing dogs, etc. In opinions such United States v. Place, 462 U.S. 696 (1983), and Illinois v. Caballes, 543 U.S. 405, 409 (2009), courts have found that canine sniffs of luggage and vehicles (and sometimes homes) are not searches and thus do not trigger Fourth Amendment scrutiny. And the basis for these rulings is that these sniffs do constitute a significant enough infringement on any reasonable expectation of privacy.

So, let's return to yesterday's post for a second. That post discussed an article and a concurring opinion arguing against the Fourth Amendment's singular focus on privacy and arguing for the recognition that the Amendment also protects other values such as security, dignity, and liberty. As noted, the concurring opinion in yesterday's post noted how this shift in focus might change the outcome in warrantless GPS attachment cases.

Well, how might this shift alter the analysis of whether search warrants/probable cause/reasonable suspicion are needed before the police call for the drug-sniffing dog, the canine dog, etc.? Well, part of the answer might be found in Has the Fourth Amendment Gone to the Dogs?: Unreasonable Expansion of Canine Sniff Doctrine to Include Sniffs of the Home, 88 Or. L. Rev. 829 (2009), by Leslie A. Shoebotham, a professor at the Loyola University New Orleans School of Law.

Part of Professor's analysis focuses upon the intrusiveness of police dog behavior. First, there is intimidation:

Although we might prefer to visualize a drug-detection dog as being a member of the U.S. Agricultural Department's "Beagle Brigade" or a Labrador retriever, like most explosives-detection dogs, such is not the case. Drug-detection dogs are often selected for the intimidation factor that they produce. The intimidation is, therefore, intentional. When asked, and sometimes when not asked, these dogs can be dangerous. Unlike an ordinary weapon, which obviously lacks a mind of its own, the potential exists for a dog, even a well-trained dog, to be disobedient. Courts that refuse to apply Kyllo in the home-sniff context on the basis that dogs are not technological devices cannot also avoid consideration of the intrusiveness that arises because dogs are not mechanical devices. Simply stated, drug-detection dogs produce fear, intentionally so, in the ordinary person. There is a societal cost associated with introducing intimidating dogs into the curtilage of a private home, and the Court has instructed that societal "understandings" are an appropriate consideration in determining reasonableness under the Fourth Amendment.

Second, there is historical oppression:

While the courts that refuse to apply Kyllo emphasize our societal recognition that dogs are familiar and have been used by law enforcement for tracking purposes for centuries, these courts ignore the fact that dogs have also been used as tools of institutional oppression for perhaps even longer. Although dogs have long been used by military forces, as early as 2500 BC, Egyptians used dogs on civilians for purposes of crowd control to protect the pyramids. The Spanish conquistadors used dogs to kill and subdue the native populations upon their arrival in America. Dogs were used to attack Native Americans and to chase down runaway slaves. During the Civil War, dogs were used to intimidate and injure African-American soldiers fighting for the North. Following Pearl Harbor, dogs were used to intimidate Japanese Americans residing in Hawaii.

In more modern times, police dogs have been used for crowd control, even on nonviolent civil rights demonstrators. The passage of time may not have healed these wounds. Recent events have again brought intimidating dogs to the forefront of our national consciousness. While the German shepherds used at Abu Ghraib prison were military trained, the fact remains that our country has an unfortunate history of using dogs to target people of color for oppression by both military forces and civilian police agencies. This sad legacy cannot be ignored in assessing the intrusiveness of introducing a police dog into the curtilage of a private home or using a dog for suspicionless screening of multidwelling residential complexes.

Third, there are potential religious objections:

Americans love dogs. It may therefore be hard for the ordinary American to fathom that many Muslims view dogs as unclean and that contact with dogs, especially canine saliva, is so offensive that it necessitates a purification ritual. Our increasingly multicultural society requires societal recognition that contact with dogs is offensive to many Muslims, however, and perhaps to followers of other religions as well. In other parts of the world, these objections are taken seriously. In the United Kingdom, for example, guidelines are being considered that would require detection dogs to wear rubber-soled "bootee" when searching a Muslim's home or a mosque. The point of this discussion is not to suggest that special rules should apply to any particular group, but rather to illustrate that contact with dogs, or contamination from dogs, is highly objectionable to some. Therefore, suspicionless entry of dogs into the curtilage of a home, or dragnet use of detection canines, must be carefully reconsidered.

Now, under the Supreme Court's current privacy-focused conception of the Fourth Amendment, courts have not found these three types of intimidation to be sufficient to render much police dog behavior "searches" that require Constitutional. But what if courts apply Justice Ginsburg's "more majestic conception" of the Fourth Amendment and recognize that it also protects other values such as security, dignity, and liberty? Do "the people' have security when they can be exposed to dog sniffs without any articulable suspicion? Is their dignity preserved with such unwarranted behavior? I think that the answer is likely "no" in many cases.



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Casey is being railroadwd

Posted by: toni | Jul 2, 2011 9:28:41 AM

I didn't really read the whole article, but from what I can see, the root of this issue is that cadaver dogs searched a car without warrant. As a note, keep in mind that there is a motor vehicle exception to a search warrant. A warrant would not be required for this car anyways.

Posted by: Tyler | Dec 2, 2018 4:59:26 PM

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