Rolf Erb, former head of the Erb Group, which went bust in 2003 with debts of CHF2 billion ($1.98 billion), died of natural causes, the Thurgau cantonal prosecutor has said.
The announcement, made on Friday, came after an autopsy conducted by the St Gallen Forensic Institute.
Erb was found dead in his home at Eugensberg Castle in Salenstein on April 8.
The cause of death was found to be heart disease.
“There are no indications that there was suicidal behavior nor of external or third-party influence,” a statement issued by the prosecutor said. The cause was found to be heart disease.external link
The collapse of the Winterthur-based Erb conglomerate was the second-largest bankruptcy in Swiss history, after Swissair. Erb said it had suffered mainly from bad real estate deals in Germany.
Rolf Erb, 65, was sentenced to a seven-year prison sentence. At the end of March, the federal court rejected an appeal by Erb, ruling that he would definitely have to serve his time.
Erb, who had rejected all accusations relating to the bankruptcy and had blamed his late father, argued he was a serious suicide risk, but the court said suicide was less likely inside prison than outside.
It was also announced on Friday that the Erb family had until the end of August before they had to leave their castle home. Originally a court had set the date to May 1.
swissinfo.ch and agencies/ilj