By Barbara Liston
ORLANDO, Florida (Reuters) - A Florida detective trying to crack a 53-year-old unsolved murder case will ask a Kansas judge for permission to exhume and extract DNA from the bodies of two notorious killers made famous in Truman Capote's 1966 true-crime novel, "In Cold Blood."
Sarasota County Sheriff Detective Kim McGath told Reuters she believes the two men convicted for the 1959 murder of Herbert Clutter, his wife and two children in Holcomb, Kansas, might be responsible for a similar killing one month later of a family in Osprey, Florida.
Capote's celebrated book about the Clutter case, written in a new style associated more with fiction than journalism, is often credited with spawning the nonfiction novel genre.
The case of the Florida family, the Walkers, has long stumped investigators. Cliff Walker and his wife and their two toddler children were shot to death in their home near Sarasota, Florida.
McGath, who spent four years reviewing half-century old investigative files on both the Clutter and Walker murders, said the exhumation of killers Richard Hickock and Perry Smith, who were executed in 1965, could provide key clues.
The hope is that DNA can be obtained from the men's long buried remains to either rule them out or connect them to the Walker murders, McGath said.
"Certain things kind of kept jumping out to me that got my attention. Certain clues that came to the forefront," McGath said.
She noted the killers in both cases shot to death parents and children, which McGath said was unusual during the late 1950s.
The Clutter children were aged 15 and 16; the Walker children were 3 and 23 months. All of the victims were shot in the head or face, McGath said.
On the run from Kansas, Hickock and Smith, both ex-convicts, stayed briefly in Sarasota County, which includes the town of Osprey, and were in the area at the time of the Walker family killings, McGath said.
One of the men had scratches on his face after the Walkers were killed, according to a witness statement.
The two were once considered suspects, but passed an early version of the polygraph test when they eventually were caught in Las Vegas. Smith had in his possession a knife identical to one stolen from Cliff Walker, who was 24.
McGath said another potential connection is that the Walkers went shopping for a green and white 1956 Chevy Bel Air on the day before their deaths.
Hickock and Smith, who were driving a black and white version of the same car, had sought work as mechanics at local gas stations and reportedly went to the home of at least one resident who was in the market to buy a car.
McGath said detectives at the time never had a prime suspect. But they did have evidence that now could be combined with DNA technology that was unavailable in the 1950s. Christine Walker, 23, was raped by her killers, and detectives found semen.
"What they did do, the early investigators, they preserved the clothing and Christine Walker's underwear," McGath said.
McGath said investigators are conducting DNA testing of the semen and the victims' clothes. Clothing belonging to Hickock and Smith is also being examined.
(This story corrects spelling of Hickock throughout, clarifies possible connection in cases in eigth paragraph)
(Editing by Kevin Gray and Cynthia Osterman)