Mark Redwine’s attorneys are asking the judge overseeing his upcoming murder trial to exclude evidence from cadaver-sniffing dogs, questioning the scientific reliability, accuracy and consistency of canines trained to sniff for human remains.

Prosecutors accused Redwine of murdering his 13-year-old son, Dylan, after the boy disappeared in November 2012. The boy’s remains were found about eight months later buried along Middle Mountain Road near Vallecito Reservoir near Redwine’s home.

Sixteen dogs trained in detecting human remains scoured Redwine’s property in the weeks and months after Dylan’s disappearance. The canines alerted trainers and law enforcement to the existence of human remains near a hamper in Redwine’s master bedroom, near a clothes washer, in Redwine’s Dodge pickup and on the clothes he was allegedly wearing the night his son went missing.

Prosecutors, in part, hinge their case on the fact that cadaver dogs “indicated that a deceased person had been in his living room and bed of his pickup truck ...,” according to the indictment.

Defense attorney John Moran, in a 39-page motion filed last month, said the findings are unreliable, the dogs used in the Redwine investigation were not properly trained, dog handlers may have biased their animals, the dogs’ findings were not corroborated by any findings of actual human remains and the evidence obtained by dogs may be given “undue weight” in jurors’ decision about guilt.

“What is at issue is what has never been proven with any degree of scientific reliability: the ability of a dog to detect the residual scent of a particular object, including human remains, at a specific location days, weeks, months or even more than a year after that object was removed,” Moran wrote. “Yet, that is precisely the speculative theory upon which the State seeks to base its case against Mr. Redwine.”

6th Judicial District Chief Judge Jeffery Wilson has yet to respond to Moran’s brief supplementing his motions seeking exclusion of evidence obtained by cadaver dogs. Wilson previously declined the defense’s request to exclude sniffing dog evidence, but he did require the prosecution to explain how the evidence meets state standards for admissibility.

District Attorney Christian Champagne addressed the admissibility of cadaver dog evidence in November, saying in three motions responding to the defense’s arguments that the evidence is reliable and that prosecutors can submit documentation to help support their case.

Champagne declined to comment, citing ethical issues in talking about an active case.

Moran argues the fallibility of scent dogs undermines the authority of evidence collected by such means. Sniffing dogs are often used in situations where low rates of success may still prove effective for law enforcement, Moran wrote. False positives from trained sniffing canines often do not undermine the reliability of a dog to get tangible results. But in a courtroom, a false positive could be the difference between a conviction or acquittal, Moran wrote.

“With such a low rate of success, the real-world implications of admitting this type of evidence against a criminal defendant in a murder trial is staggering, particularly in cases where no human remains were found at the ‘alert’ locations,” Moran wrote.

It’s also impossible to know what dogs are thinking, and it is up to interpretations from trainers, who may be biased by law enforcement, to translate the dog’s actions into factual claims, Moran wrote.

Judge Wilson has an explicit role as a gatekeeper concerning the admissibility of evidence, Moran said. In the case of cadaver dogs, it is Wilson’s duty to recognize “the underlying science is both unreliable and acutely complex, but will be viewed by a jury as common knowledge and treated as fact,” Moran wrote.

“Where the evidence offered is unreliable and will result in extreme prejudice to a defendant, the court must exclude it,” Moran wrote.

Attorneys in the Redwine trial are barred by gag order from speaking about the case.

Wilson said he plans to rule on the motion to dismiss cadaver dog evidence before a week-long motions hearing scheduled to begin June 24.

bhauff@durangoherald.com