Cadaver Dogs: Canis Familiaris

by Andrea Campbell

Cadaver dogs are canines, Canis familiaris, which are specially trained to find human decomposition scent and alert their handlers to its location. They are used in a variety of forensic contexts, including search and discovery of human cadavers, body parts, or body fluids. In contrast to bloodhounds or other tracking dogs—which locate a specific scent on the ground or an item—cadaver dogs are trained to detect generic scent in the air.

In particular, these dogs are conditioned to give an alert to the scent of human decomposition. They are sensitive to the odor given off by newly dead bodies, which may lack any obvious signs of decomposition. They will also alert to decomposing bodies, to skeletal remains, or even to soil contaminated with human decomposition fluids. Because of the sensitivity of air scent dog olfaction, even buried bodies or bodies dead for 20 or more years can be detected in certain circumstances!


The first dog trained exclusively for cadaver search by a police department began work in 1974. The NY State Police were investigating a homicide in Oneida County that involved multiple buried victims in a large forested area.

Increasingly, the cadaver dog/handler unit is part of a multi-disciplinary search team including medical examiner, anthropologist, and law enforcement members, among others.

Dog Selection and Noses

If the dog is chosen solely for air scent work, the principle drive is the prey drive. Bas ically, you should look for a dog that is “ball crazy.” The dog should follow the movement of the ball. . . . A dog that is adaptive to new sites, one that is not startled by loud noises and recovers easily, are good traits.

All animals directly sense chemical molecules. This is true even in animals that lack a nose. Bacteria are known to sense and cluster about certain chemicals. Flies sense molecules through their feet. Human beings have approximately five million olfactory receptor cells. A bloodhound has 100 million such cells.

Scent Cone Theory

Scent is produced when molecules from an object are dispersed into the air and register a sensory reaction in the brain. Molecules shed by the object become more and more dispersed the farther away from it they move. This concentration gradient theoretically forms a scent cone. Mammals are able to detect both the presence and the relative concentration of scent. Interruptions to, and enhancement of, the spread of molecules from the source may distort the scent cone.

Decomposition Process

The decompo sition process commences immediately after biological death occurs and proceeds through five stages before the body is completely skeletonized. Certain elements are necessary for the process to occur. These elements affect how rapidly the remains proceed through the stages. The decay process produces a variety of gases, liquids, and acids. It is these by-products that provide the odor that the dog is trained to recognize and indicate. There are two special situations with different scent results: If a body decomposes in a wet environment, the adipocere, a grayish, soapy substance provides a good scent picture to the dog. If the body is left in a hot, dry environment it will mummify, and the odor will be musty, also recognizable by the animal.

Stages of Decomposition and Odor Characteristics

  1. FRESH: Little or no exterior change; however, is decomposing internally due to bacteria present in the body before death. Odor: None detectable by humans; however, animal may show reaction or approach body as if it were still alive. Dog may detect at some distance.

  2. BLOATED: Body swollen by gas produce internally. Insect activity may be apparent. Odor: Decay odor present. Detectable by bot dog and human. Can be detected at a distance.

  3. DECAY: Body collapses as gas escapes. Exposed flesh may be thick. Odor: Strong putrefaction odor detectable by dog and human at some distance.

  4. LIQUEFACTION: Liquids created during the decomposition process seep into the environment. Body drying out. Odor: Reduced odor production. May smell cheesy or musty. Animal may still detect at a distance.

  5. DRY/SKELETAL: Slow rate of decay. Remaining flesh may be mummified. Odor: Musty odor. Detection distance shortened.
    *Detection distance varies with wind direction, weather and terrain. If approaching upwind, detection distance will be much greater than if working with wind at the handler’s back.

Elements of Decomposition

Microorganisms: Normally present in the lungs and intestinal tract. Many are necessary in a living person for normal functions. If death is the result of disease, pathological organisms may be present.

Warmth: Decomposition is significant at approx. 50°F and proceeds most rapidly between 70° and 100°F. Between 100° and 212°F, the process slows as the reproduction of bacteria is retarded by the increased temperature and moisture is evaporated.

Air: Oxygen-consuming organism activity is retarded by the absence of air. Restriction of airflow around remains will slow the decomposition process.

Moisture: Microorganisms require moisture to function. A body normally contains enough moisture for the bacteria to multiply.

Principles of Scent Cone Presence and Distortion

  1. Decomposition odor will tend to form a scent pool above and around the remains.

  2. Air flow will move the scent away from the source in the direction of the wind, forming an air scent cone.

  3. Water will move the scent away from the source along scent conduits in response to gravity or currents, along surface of underground waterways; or following erosion or drainage patterns.

  4. Wind or water flow can be altered by scent barriers.

  5. Water flow along a conduit can interrupt the absorption of scent into the soil near the remains causing a scent void near the remains at the dog-nose level.

  6. Variable wind patterns can cause an uneven distribution of scent molecules in the air.

  7. Elevation of the body with a horizontal scent cone can produce a scent void near the remains at dog-nose level.


Understanding the natural processes that influence outdoor death scenes is vital to the success of conducting and interpreting searches. The study of what archaeologists and paleontologists calls “death assemblages” is termed taphonomy, which literally means the laws of burial, but can refer also to unburied bodies exposed on the earth’s surface. In other words, taphonomy includes knowledge about the process by which a body is transformed from a living being to dust—or fossils, chemical constituents, or mummified remains. In forensic taphonomy, we are concerned with the earliest part of that postmortem period.

Legal Issues

When conducting a search, a dog/handler team is, in effect, searching for evidence. Most of the legal cases regarding dog searches deal with drug seizures, but the principle under which the issues are raised apply equally to cadaver dog searches. The two primary areas of concern are the acquisition of evidence and the acceptance of that evidence by a court. Unless the search team is operating within the guidelines set down by the Constitution and the court system, any evidence located during the search may not be admissible at a trial.

• The Fourth Amendment of search and seizure is the applicable standard. No warrant will issue without probable cause.

What constitutes a search with a dog? The court decided in United States v. Place, that the activity of a drug-sniffing dog was unique. The dog only alerted if there was evidence of contraband. Therefore, the dog was only disclosing criminal behavior and a warrant was not necessary. No intrusion of an innocent person’s privacy would occur.

Many courts have allowed searches by air-scent dogs without a warrant when the search has been based on other facts that gave the police a reasonable suspicion. Courts, however, will not allow dogs to be used for general exploratory or dragnet-type searches. The decisions in these cases appear to be very fact specific. The court’s decision to allow lesser evidence or exigent circumstances to be substituted for the need to obtain a warrant remains unpredictable.

The issues above rarely occur in the context of cadaver dog searches. These searches are usua lly the result of prior investigation. Cadaver searches by their very nature will lack exigent circumstances except in the rarest of cases. Those cases will usually involve the suspicion that a vehicle either has a body in it or was used to transport a body.

The principle area of concern for cadaver dog handlers is the possibility of warrantless entry onto property where there is a justified expectation of privacy. Open fields are not protected by the Fourth Amendment. The surrounding area or curtilage—areas adjacent to structures—requires a warrant. With public land there are no privacy issues involved.

There you have it: the working cadaver dog.

No charges forthcoming in Garza case

By Adam Silverman

Free Press Staff Writer

Authorities have found no evidence to warrant criminal charges in the case of Nick Garza, a Middlebury College student who vanished and drowned in February, police said Wednesday, three months after searchers found the freshman's body.
Garza, 19, of Albuquerque, N.M., used a fake ID to buy alcohol Feb. 3, and the transaction was captured on surveillance cameras, Middlebury Police Chief Tom Hanley said. Garza brought the drinks to share with five friends during a dorm-room gathering two nights later, the last time he was seen, Hanley said.

Search dogs tracked Garza's scent on a winding path from Stewart Hall to Otter Creek, where investigators believe the inebriated student missed a sharp turn onto a footbridge and fell into the icy water, Hanley said.

"There's absolutely no evidence of anything criminal here," the chief said. "We'll never be able to say definitively that he did precisely this, this and this, because there are no witnesses, but there's nothing factual we've found that conflicts with anything."

Addison County State's Attorney John Quinn said he reviewed the case with investigators and agreed with their assessment. Neither charges nor an inquest is necessary, Quinn said.
"I did not see any indication of foul play," Quinn said. "The Middlebury Police Department's investigation was thorough and complete."Alcohol-related charges are unlikely, too, because Garza provided the booze, Quinn said.

"Unfortunately, it seems we had an intoxicated Middlebury College student who walked off that night and fell into the creek and died," he said.An autopsy and report from the Medical Examiner's Office could not determine the cause and manner of Garza's death, Quinn said.
The student's mother requested a second opinion, Hanley said, and the "very, very thorough" report has been forwarded to Dr. Michael Baden, a prominent forensic pathologist. Hanley declined to release additional information, such as the state's medical findings or the location of the alcohol purchase, until Baden's work is complete, likely within a month.

Garza's last known location was outside Stewart Hall, across campus from his own residence hall, as he left the Feb. 5 gathering just past 11 p.m. He wore sneakers but no coat despite cold weather; a snowstorm began early the next morning. His cell phone stopped working within eight hours of his disappearance.

Friends first thought Garza might have left campus for the final days of winter break, but when he didn't return, his family reported him missing. Relatives flew to Vermont to oversee the search, which unfolded over months rather than days or hours as loved ones and the Middlebury College community had hoped.

Investigators, pursuing the theory Garza was in Otter Creek, were preparing to remove a large pile of logs and other debris from the water May 27 when they discovered human remains. Dental records confirmed the body was that of Garza.

Dog collars teen vandal suspects

Thursday, August 28, 2008, 07:58

A POLICE dog has helped to collar a gang of teens suspected of causing thousands of pounds worth of damage to a school.
Handler Constable Carl John and four-year-old Dutch were called to Ysgol Gyfun Gwyr in Gowerton after reports of a break-in.
Dutch, a Belgian Malinois, got to work sniffing for clues and soon picked up a scent.
Dog and handler tracked the scent through the school and out onto open ground where Constable John saw someone walking away.
The person began running when told to stop by the officer — but Dutch was released and chased down and caught the suspect.
The crime-fighting hound then resumed searching the school and found a discarded piece of clothing and other items believed to have been used to cause damage.
Three more people were arrested by officers near the school a short time later.
A Swansea Council spokeswoman said: "The final cost incurred by the incident at Gwyr has not been finalised but will be between £2,500 and £4,000.
"Vandalism of our schools is not a victimless crime and causes distress to pupils, parents and staff, as well as being a pointless waste of public money."
It is thought the vandals smashed more than a dozen glass panels in the school entrance area.
The incident happened on August 4, but the details have only just been released.
Two 17-year-old males, a 17-year-old female and a 16-year-old girl have been quizzed over the incident and are on police bail pending further inquiries.
Inspector Mark Hobrough, from South Wales Police's dog, mounted and specialist search and recovery team, said: "The force's specially trained dogs provide invaluable support to police officers on a daily basis by apprehending criminals, uncovering evidence and sniffing out drugs, as well as displaying many other skills."

Utah County Sheriff's Office receives a donated bloodhound

Thursday, 28 August 2008

Joe Pyrah - Daily Herald

Sure, its floppy ears and wet nose are cute now, but you're not going to think so when you're on the run from the law in 12 months. The Utah County Sheriff's Office received a donated bloodhound on Wednesday that will be used exclusively to track people, whether criminals or lost kids.

"Genetically, those dogs are pretty much bred and used for tracking applications," said Sgt. Lane Critser, K-9 supervisor for the department.

The 8-week-old unnamed pooch is courtesy of Child Protection Education of America, a national private foundation addressing missing and exploited children.

The age is both a benefit and a drawback. It will likely be 12-18 months before she can be used officially to find people. There's also a chance that the dog simply won't take to the training and be nothing more than man's best friend.
"Normally that's why we pick up dogs that are within 2 to 3 years of age," Critser said.

But the county has eight dogs already and plenty of experience training them. Five are normal patrol dogs, one is with a special unit, and two are bomb-sniffing dogs. (Each of the full-size dogs goes through a 40-pound bag of dog food every six weeks.)
The bloodhound will be going home nightly with detective Shawn Radmall and will be getting "as much socialization as it can" in the next month or so, Radmall said. That's when the formal training begins.
When complete, the dog will be able to track in urban, rural and wilderness areas. She doesn't have a name yet, a problem that kids of the Sheriff's Office employees are working to remedy in a contest.
Why bloodhounds?

  • Renowned for their scent-tracking ability, bloodhounds have 60 times the scent power of German Shepherds.

  • Proper training only improves the breed's natural tracking abilities.

  • Scent evidence is sometimes the only evidence leading from the crime scene to the perpetrator or the victim.

  • Scent evidence is admissible in most courts of law, if the prosecution lays a proper foundation.

  • The olfactory ability of a bloodhound is more than 1 million times stronger than that of a human.

Source: Child Protection Education of America