Family members denied a report by the online magazine RadarOnline.com that said McGraw was paying to have Zahau's body exhumed and retested for evidence of foul play, KNSD-TV, San Diego, reported Tuesday.
The family said it is paying for the exhumation out of a donation fund.
Zahau was found dead July 13 in her boyfriend Jonah Shacknai's San Diego mansion. Her body was hanged and her feet bound, She died just days after Shacknai's 6-year-old son fell down the stairs while he was under the woman's care. The boy later died of his injuries.
Investigators have ruled the death a suicide but skeptical family members say there are unanswered questions. "We, her family and friends, do not believe it's a suicide," Zahau's sister, Mary Zahau-Loehner of Missouri, told The San Diego Union-Tribune last month.