ST. PETERSBURG, Fla. — A bid to solve a decades-old quadruple murder in Florida failed Tuesday when sheriff’s deputies said they could not link DNA to the two killers profiled in the book ‘‘In Cold Blood.’’
The convicted killers, Perry Smith and Richard Hickock, were long suspected in the slayings of Cliff Walker; his wife, Christine; and their two children. The family was killed in December 1959, about a month after Smith and Hickock murdered a Kansas farmer and his family.
Captain Jeff Bell of the Sarasota County Sheriff’s Office said authorities were unable to make a match between the pair and Christine Walker, who was raped and had semen on her underwear.
Authorities said only partial DNA profiles could be taken from the exhumed bodies, and the Walker crime scene samples were degraded. No more tests were scheduled.
‘‘It wouldn’t exclude them but it also does not provide us with any level of confidence to say there’s a match because there’s not,’’ Bell said.
Police still believe the two men were probably involved.
“The mystery continues and we’ll look for other opportunities,’’ Bell said.
Testing decades-old DNA can be difficult, said Dr. Michael Baird, the laboratory director of the DNA Diagnostics Center in Ohio. He said genetic evidence can degrade over time. How much DNA was retrieved from samples, how it was stored, and the conditions it was exposed to all play a role in whether a full DNA profile can be collected.
Smith and Hickock fled to Florida after killing prominent Kansas farmer Herb Clutter, his wife, and two of their children on Nov. 15, 1959.
The murders in Holcomb, Kan., were chronicled in Truman Capote’s book, which gripped readers with its vivid narrative of the tormented inner workings of the killers’ minds. The killers were executed.
On Dec. 19, the two men checked out of a Miami motel. The Walker family was killed that day at their home on a ranch in Osprey about four hours northwest of Miami.
Cliff Walker was shot to death and his wife was beaten, raped, and shot. Three-year-old Jimmie was shot to death and his 2-year-old sister was shot and drowned in a bathtub.
The two men — who were drifters — were eventually captured in Las Vegas. A polygraph test cleared them of the Walker murders. But in 1987, a polygraph specialist said those tests in the early 1960s were worthless.