Levert, 39, was taken from the Cuyahoga County jail in Cleveland on Sunday night after suffering from high blood pressure and hallucinations, but died within the hour at Lutheran Hospital.
Cuyahoga County jail, warden Kevin McDonough said Levert had been sick and guards were watching him at the jail's regular cellblock because he had been acting strangely.
"There was nothing that would show any of this," McDonough said. "He had an illness while he was here and it turned into an emergency at that time."
Last week Sean was sentenced to one year and 10 months in jail for failing to pay $85,000 in child support.
Sean was the second brother of the R&B trio LeVert to pass away. Gerald Levert was 40 when he died in 2006 of an accidental mix of prescription and over-the-counter drugs.