SEOUL, South Korea — The head of a South Korean savings bank appeared to have jumped to his death on Friday, police officials said, as prosecutors expanded their investigation into an alleged corruption scandal by raiding his and six other banks and seeking to arrest a former senior aide to President Lee Myung-bak.

Jeong Gu-Haeng, president of Jeil 2 Savings Bank, was found dead after apparently jumping from his office on the sixth floor of the bank’s headquarters in downtown Seoul, a police spokesman said, insisting on anonymity until his agency made an official announcement. People who were entering the bank witnessed Mr. Jeong falling, the spokesman said.

“He apparently jumped from his office,” he said. “It looks like a suicide.”

The man jumped as prosecutors, police and bank regulators raided seven savings banks, including Jeil. They were searching for evidence of alleged irregularities by their executives and major shareholders, such as excessive loan extensions and bribery.

Last Sunday, financial regulators suspended the operation of the seven banks for six months, citing their poor financial condition. So far this year, they have suspended 16 savings banks after their investments in real-estate developments and other misbehavior damaged their liquidity.