Fort Bend County Sheriff's Deputy Keith Pikett announced his resignation last week, saying he was ready to "hang it up," Sheriff Milton Wright said.
Pikett is the defendant in at least three pending lawsuits from men who say they were wrongly jailed after the deputy's dogs linked them to crimes. Authorities eventually dropped charges in the cases.
The sheriff and Pikett's attorney said the 63-year-old deputy's retirement is unrelated to the lawsuits. They did acknowledge, however, that new cases slowed to a trickle as law enforcement agencies stopped calling Pikett for help.
"The adverse publicity has certainly shut him down - at least out of county," Wright said.
Pikett did not respond to messages left by The Associated Press. Fort Bend County Attorney Randy Morse, who is defending Pikett in the lawsuits, said the deputy was at retirement age and will maintain an affiliation with the county as a reserve deputy.
Pikett has spent the last two decades training dogs named Clue, James Bond and Columbo to sniff out possible criminals in more than 2,000 scent identification lineups.
During a scent lineup, pieces of gauze or cloth are used to take scent samples from a suspect and others, and then placed in separate coffee cans. A dog is presented a piece of crime scene evidence and then led by Pikett to each can for a whiff. The dog is supposed to signal Pikett if it sniffs a match.
Pikett says his dogs are accurate, and Wright praised him as a "good deputy." Pikett consulted for the FBI; the Bureau of Alcohol, Tobacco, Firearms and Explosives; the Texas Attorney General's Office and several Texas police and sheriff's departments.
But some in the legal community have derided Pikett's techniques as junk science with no place in police investigations or the courtroom.
Jeff Blackburn, the founder and chief counsel for the Innocence Project of Texas, said it was "no surprise" Pikett stepped down after being "exposed" in the lawsuits.
"The problem is not Pikett," said Blackburn, who represents three plaintiffs in a lawsuit against the deputy. "The problem is the system that allowed Keith Pikett to become a star witness for the state."
In two lawsuits filed in Victoria, the plaintiffs accuse Pikett of manufacturing evidence and say his scent lineups are merely an "elaborate performance."
One of the plaintiffs is a former captain in the sheriff's department who was accused of killing a state social worker. The other plaintiff spent two months in jail, wrongly accused of the robbery of one elderly woman and the sexual assault of another.
The third lawsuit was filed in Houston on behalf of three men, one of whom was charged with capital murder and held in jail without bond for 16 months. The other two plaintiffs spent nine months and eight months in jail, respectively.