"We have a lot of questions that need to be answered," Vicki Lynn Saunders told The Associated Press about the death of her father, Nelos Richard Sills. "We want answers."
The Monroe County Sheriff's Office closed the case in November, saying it was too old and that the investigation would cost too much to continue.
Mr. Sills' death was ruled a suicide in 1965, when he was married to Betty Neumar. Florida investigators reopened the case in June after Mrs. Neumar's arrest in North Carolina in the 1986 death of her fourth husband, Harold Gentry.
Police have also begun to re-examine the deaths of her first child -- Gary Flynn, whose 1985 death was ruled a suicide -- and three husbands, though she faces no charges in those cases. Authorities recently closed their re-examination of the death of her fifth husband, John Neumar, of Augusta, saying they have no evidence she was involved.