A police spokesman in Jupiter, Florida, told CNBC the death is not classified as suspicious but investigators are awaiting toxicology results.
Bill Ash, who said he was Tobias' assistant, told CNBC he had taped proof that Tobias was a murder victim and said he has been working with police.
"I think I'm doing more for Seth than anyone as far as trying to right a wrong," said Ash.
Police said they interviewed Ash at his home in San Diego after he came forward with information. They noted that Ash has a checkered past. Ash acknowledged to CNBC that his record includes arrests for prostitution and writing bad che
Meantime, Tobias' wife is engaged in a legal battle with his four brothers over the estate, estimated to be worth at least $25 million
Attorneys for both sides declined to comment but Ash is scheduled to give a deposition in the estate battle on Monday.
The $87 million fund manged by Tobias is being liquidated, according to an attorney for the fund. Two other Circle-T funds run by other managers remain intact.