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.

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 Hickok 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.

On the run from Kansas, Hickok 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.