(CNN) -- A major investor in convicted swindler Bernie Madoff's Ponzi scheme drowned in his swimming pool in Florida after a heart attack, his attorney said Monday. The medical examiner's office confirmed the report.
Jeffry Picower, 67, was found unconscious in his pool shortly after noon Sunday at his Palm Beach, Florida,, home by his wife, Palm Beach police said. He was pronounced dead at Good Samaritan Hospital.
Picower's attorney, William Zabel, told CNN that Picower drowned after suffering a massive heart attack. Sue Jaffe, spokeswoman for the Palm Beach County medical examiner, confirmed those details.
In September, Forbes magazine ranked Picower No. 371 among the 400 richest Americans, with a net worth of $1 billion.
In March, Madoff was convicted of operating a Ponzi scheme and defrauding thousands of investors. He was sentenced to 150 years in prison after pleading guilty to 11 felony counts of fraud, money laundering and perjury. Prosecutors have said it was the largest investor fraud ever committed by a single person, totaling billions in losses to investors.
When the Picower Foundation of Palm Beach announced it was shutting down early this year because of Madoff losses, it initially appeared that the prominent philanthropist had been an unfortunate victim of Madoff's Ponzi scheme. Picower's 2007 tax return had valued his foundation's portfolio at $955 million.
However, in May, court filings by Madoff trustee Irving Picard changed the picture. The trustee's complaint claimed that Picower had been a key beneficiary of Madoff's Ponzi scheme for more than 20 years, and "knew or should have known that [he] was profiting from fraud because of the implausibly high rates of return" on his accounts.
Those "anomalous and astronomical rates of return" -- as high as 500 percent in one year and 950 percent in another year -- "were neither credible nor consistent with legitimate trading activity, and should have caused any reasonable investor ... to inquire further," the court filings said, referring to Picower as "a sophisticated investor, accountant and lawyer."
Citing backdated account filings and other bogus paperwork, the complaint contends that "Picower and the other defendants also knew or should have known that they were reaping the benefits of manipulated purported returns, false documents and fictitious profit."
The Picowers recently told The New York Times that the publicity and controversy surrounding their connection to Bernie Madoff had been a great source of heartache.
"We always have been private people, and having all this play out in the media has taken a big toll on our health," the couple wrote in response to questions posed by reporters.
"We feel stunned, betrayed, angry, sickened, devastated," they said, and were only able to draw strength and consolation "from each other and from the knowledge that we did nothing wrong."