The mystery surrounding the untimely death of R&B singer Sean Levert in a Cuyahoga County jail has taken a sinister turn and Sean's family has asked the FBI to investigate. While staff at the jail claim Sean was “out of control” and “hallucinating,” forcing them to place him in a restraining chair, his family doesn't believe that, stating Sean never had any outbursts like those before. The 39-year-old singer died Sunday night at a hospital after he was taken from the county jail where he was serving a one year and 10 months sentence for failure to pay $89,025 in child support. Warden of Cuyahoga County, Kevin McDonough, said Sean was pounding on his cell door so guards strapped him in a restraint chair; his breathing became shallow and he was taken to Lutheran Hospital, where he died less than an hour later. An autopsy did not determine the cause of death. Toxicology tests are expected to take weeks. FBI spokesman Scott Wilson says agents would meet with the Levert family.