Witnesses have said they spoke with Smith and Hickock in Tallahassee on Dec. 21.
McGath said the Walkers were considering buying a 1956 Chevy Bel Air, the kind of car Smith and Hickock were driving through Florida. McGath thinks the Walkers met with the men because of the car.
Smith and Hickock were later arrested in Las Vegas. A polygraph test cleared them of the Walker murders, but a polygraph expert said in 1987 that such tests were worthless in the early 1960s.
"Sometimes you just have to wait for the technology to catch up to the need," Kyle Smith said.
Hickock and Perry Smith are buried on a gently sloping hill at the Mount Muncie Cemetery in Lansing, where the state of Kansas interred executed criminals when their families didn't claim the bodies. The cemetery regularly draws visitors who have read Capote's book or have seen a movie about him or the case.
The exhumation began shortly after sunrise Tuesday and ended by noon. Bone samples were collected, and the bodies reburied, Kyle Smith said. Reporters and other members of the public weren't invited to view the work because investigators were treating the graves as crime scenes.
"It went about as well as it could have," cemetery manager Gene Kirby said. "There were no surprises."
The KBI will take DNA from what was bone marrow, Kyle Smith said. He said one of its labs will do the analysis behind higher-priority tests for criminal cases about to go to trial, and he wasn't sure how long it would take.
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