Authorities said Monday that an autopsy was inconclusive but foul play was ruled out.
Levert was sent to the Cuyahoga County jail last week for failing to pay child support. He died at Lutheran Hospital in Cleveland late Sunday, less than an hour after he was taken there from the jail, said coroner Frank Miller.
The family issued a statement Monday afternoon saying: "There are no words that can express what we are feeling today. There is no song that can capture the loss that we have in our hearts. But we are humbly overwhelmed by the generous outpouring of love, condolences and support from the many friends, fans and admirers of our son Sean. At this very difficult time, we thank you for your prayers and hope you will understand our need for privacy."
Record producer Edwin "Tony" Nicholas, a long-time collaborator with members of the Levert family, said that Sean Levert was devasted by the death of his brother.
"I'm even wondering if that had something to do with why he's not here now," Nicholas told the Cleveland Plain Dealer in an interview Monday.
"Sean was just a joy to be around. ... You just couldn't get mad at him. He was always good-natured, just an all-around fun guy."
The Levert brothers and childhood friend Marc Gordon were part of the R&B trio LeVert. Their hits included "(Pop, Pop, Pop, Pop) Goes My Mind" and "Casanova."
"Casanova" was nominated for a Grammy in 1988 for best R&B performance by a duo or group with vocal. It was also nominated for best R&B song.
At Gerald Levert's funeral service in November 2006, Sean Levert and his father performed "Dance With My Father" and personalized the words for Gerald. The elder Levert's group, the O'Jays, was known for such smash hits as "Back Stabbers" and "Love Train."
The autopsy done Monday provided no immediate evidence of cause of death, according to Powell Caesar, a spokesman for the Cuyahoga County's coroner's office.
Levert suffered from high blood pressure and had been hallucinating in jail, Caesar said. Toxicology reports could take four to six weeks, he said.
Warden Kevin McDonough said earlier that Levert had been sick and guards were watching him at the jail's regular cellblock because he had been acting strangely.
Sean Levert had pleaded guilty last week to six counts of nonsupport involving children ages 11, 15 and 17.