July 14 (UPI) — Florida on Tuesday is set to execute a man convicted of murdering a woman at a 1982 New Year’s Eve party then disposing of her remains, which have yet to be found.

Dennis Sochor’s lethal injection is scheduled to take place at 6 p.m. EDT. If executed, he will be oldest person in the state’s history to be put to death at 74, The Palm Beach Post reported.

The Florida Supreme Court has denied Sochor’s appeals to stop the planned execution. His lawyers have taken the case to the U.S Supreme Court, arguing that previously executed prisoners showed evidence of pulmonary edema as a result of the lethal injection.

Pulmonary edema causes fluid to build up in the lungs and creates the sensation of drowning. Sochor’s lawyers argued the drug that’s supposed to prevent a person from feeling the effects of the pulmonary edema wore off before they died.

Sochor was convicted of killing Patty Gifford after both attended a New Year’s Eve party. Police say Sochor sexually assaulted and then strangled Gifford in his vehicle. He then disposed of her body and never told anyone her whereabouts.

Gifford’s family said they hope Sochor will reveal the location of her remains.

“It’s unfinished,” Patty Gifford’s sister, Marilyn Gifford, told CBS News. “Where is she? What did he do to her? Where did he leave her? It just matters. It matters so much.”

She said, though, that Sochor’s execution will allow the family some peace and closure.

“I expect to sleep like a baby tomorrow night for the first time in decades,” she said.