Scent-lifting Device Under Fire

What do Dogsters who work with Search and Rescue or similar areas have to say about this device? Bark in! Thanks to the LA Times...

Joy  |  Dec 9th 2006


What do Dogsters who work with Search and Rescue or similar areas have to say about this device? Bark in!

Thanks to the LA Times for this article.

Device that helps dogs sniff out suspects may not be up to snuff
Scent-lifting machine is popular with law enforcement because it preserves evidence, but critics say there’s no proof it works. Numerous cases have been dismissed.
By H.G. Reza, Times Staff Writer

A device promoted as a law enforcement tool to help bloodhounds detect human scents at crime scenes has come under increasing fire after its use in recent years has led to the incarceration of at least five men whose cases were later dismissed.

In the latest case, a Buena Park man was freed from prison in October after serving almost a year for a carjacking and armed robbery he did not commit. He was released only after a man jailed in Los Angeles County admitted to the crime, a confession supported by DNA evidence.

The scent-lifting device, known as a scent-transfer unit, or STU-100, was invented in the 1990s by Newport Beach engineer Larry Harris and a partner who has since died. Harris and a small band of Southern California supporters a group derided by the bloodhound-handling world as “social outcasts” have promoted the $900 machine to law enforcement.

Its backers say the machine, which resembles a leaf blower, can collect human scent from an object as small as a bullet fragment and transfer it to a 5-by-9-inch gauze pad that is put to a bloodhound’s nose. The dog then theoretically follows the scent to the suspect.

The machine allows the scent to be presented to the dog without compromising physical evidence. But there is debate in the academic community over whether bloodhounds can reliably identify a specific suspect by his scent under any conditions.

It is unknown how many arrests or convictions can be attributed, at least in part, to the device because most law enforcement officials, including the FBI, declined to comment or did not return phone calls.

Civilian dog handler Ted Hamm, for one, says he has used the device in most of the 2,000 cases he has worked.

Despite its heavy use in law enforcement, critics say there is no hard evidence that the device works.

“I think it’s quackery,” said Larry Myers, professor at Auburn University’s College of Veterinary Medicine and an expert defense witness in scent evidence cases. The dog handlers “have no idea how reliable the machine is.”

In 2003, a California appellate court limited the use of scent evidence in state trials, ruling that the device and its operators have to meet standards that are “generally accepted” as reliable by the scientific community a benchmark that has not been achieved. Still, law enforcement continues to use the machine to identify suspects or gather enough probable cause for an arrest or search warrant.

“It’s just one piece of the big investigation puzzle,” said Lt. Larry Lincoln, a Los Angeles County sheriff’s homicide investigator.

Agencies including Irvine, Buena Park and Long Beach police, the arson unit in Riverside County and the FBI have used the device.

I. Lehr Brisbin, a specialist in animal behavior and canine olfaction, said tests had shown that bloodhounds despite their uncanny ability to detect human smells are often unable to sniff out the originator of a scent among a group of people.

“The folks making these claims never allow their dogs to be tested” independently, said Brisbin, a professor emeritus at the University of Georgia. “But I don’t think it’s intentional fraud. It’s a case of ultimate faith and belief in the machine and dog, but not in science. It’s like a religion.”

Harris declined to comment for this article, but Brisbin and Myers said the handlers who use the scent-transfer unit had been unable to explain how it works. This has hampered the admissibility of evidence gathered by the machine in state courts.

“I’m a dog guy, not a scientist,” said Hamm, the only dog handler using the device who would be interviewed for this story. He works with the Los Angeles County Sheriff’s Department at $125 per hour. “I can only say that I know it works through a lot of informal training. If people are willing to try and spend time with the dogs, they’ll end up having a lot of success” with the machine.

Defense attorneys complain that the real value of the device is to give police probable cause to arrest a suspect when there is no physical evidence linking him to a crime.

“Larry Harris’ dog was the excuse the cops needed to zero in on my client,” said Santa Ana attorney Scott Borthwick, who represented James Ochoa, the man who was falsely accused of carjacking and robbery and released from prison in October. “Never mind that he was innocent. And that the dog walked past his house four times. And that it was the only house on the block surrounded by cops. Where else was the dog supposed to go?”

Though Harris has sold the machine nationwide for a decade, it is best known for its use in Southern California, where about 10 operators known in law enforcement circles as “Harris’ disciples” use the scent-transfer unit in criminal investigations. The 10, who include civilians and police officers, make up the Southern California Bloodhound Handlers Coalition.

Their machine and dogs have led to false arrests in several high-profile cases.

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