TALLAHASSEE, Fla. — A lawyer for a drifter who was convicted of beheading two women and killing an elderly couple in the forests of three Southern states asked the Florida Supreme Court on Thursday to reverse his conviction and death sentence in the only one of the slayings that resulted in a death sentence.Gary Hilton, 65, received a life sentence in Georgia, where he pleaded guilty to killing 24-year-old Meredith Emerson of Buford, Ga. A Tallahassee judge last year sentenced Hilton to death for the murder of Cheryl Dunlap based on a unanimous jury recommendation. The 46-year-old nurse from Crawfordville was killed in north Florida’s Apalachicola National Forest.Hilton’s lawyer focused his oral argument on comments made during the trial’s penalty phase by the state’s expert mental health witness.Dr. Gregory Prichard “was permitted to testify to allegations of uncharged, unsubstantiated prior crimes that included fraud, theft and — most inflammatory — sexually molesting children,” Assistant Public Defender William C. McLain said.The clinical psychologist testified that Hilton’s ex-wife had told Georgia authorities he molested her two young children, a girl and a boy, in the 1970s.McLain called that “double hearsay” and noted the state presented no evidence to substantiate the woman’s claim her children were molested. He also objected to Prichard’s mention of comments from Hilton’s former employer who said Hilton told him of making a movie about hunting down and killing women in the forest.