Jeffry Picower, the billionaire philanthropist and big Bernard Madoff investor, died after suffering a massive heart attack in his Palm Beach, Fla., pool, the medical examiner has ruled.

Picower drowned on Sunday as a result of the heart attack, according to the Palm Beach County Medical Examiner, which performed an autopsy yesterday. “The autopsy performed on Jeffry Picower found that the cause of death was drowning as a result of a massive heart attack,” Picower’s lawyer, William Zabel, said in a statement.

Picower was at the center of two ongoing battles over the huge Madoff fraud, one criminal, the other civil. The court-appointed receiver in the Madoff case, Irving Picard, was seeking the return of billions from Picower, alleged to have withdrawn more than $7 billion—about $5 billion of it in phony profits—from his Madoff accounts over the years. He was the single-largest beneficiary of the Madoff fraud, according to Picard.

But prosecutors had also reportedly found evidence that Picower had picked how high his returns, which ranged from 300% to 950%, would be. Picower had not been charged with a crime at the time of his death, but Picard said his accounts “were riddled with blatant and obvious fraud.”

Picard vowed to continue his lawsuit against the Picower estate and foundation.