Guenter Kaussen, a financially troubled landlord with extensive property holdings in West Germany and the United States, hanged himself in his apartment here, officials reported Monday.
A government statement said Kaussen's body was discovered Monday morning. No suicide note was found, but authorities ruled out foul play.
Kaussen, 57, owned between 16,000 and 20,000 apartments throughout West Germany, officials said, and was considered the country's biggest landlord. He also owned several thousand apartments in San Francisco and Atlanta, and had been under investigation for suspected improper business practices.
The statement quoted Kaussen's tenants as saying he had been behaving strangely recently. Last weekend, Cologne police rescued some of Kaussen's employees after he locked them in his office.
He was believed to be $133 million in debt, with $45 million owed to creditors in the United States. His real estate investments in the United States were believed to have resulted in heavy losses. Although he reportedly earned about $1.3 million annually from rents in West Germany, it was not enough to pay off mounting debts.
It was not immediately clear who would take over Kaussen's holdings, which in San Francisco included 25 properties with more than 1,500 apartments.