Prosecutors are looking into additional bribery allegations linked to former President Lee Myung-bak, who is already under probe over an extensive corruption scandal.

The Seoul Central District Prosecutors’ Office is investigating suspicions that one of Lee’s close aides accepted hundreds of millions of won from Daebo Group, which runs rest areas on expressways, in 2010 in return for helping the company win government contracts, sources said Wednesday.

The chairman of Daebo Group is currently serving a three-year jail term for embezzlement. Suspicions of collusion between Daebo and the state-run Korea Expressway Corp. were raised during parliamentary audits, as the company won several contracts to operate expressway rest areas.

The prosecution is also investigating a former head of a major financial services company on allegations that he gave over 2.2 billion won ($2 million) in kickbacks to the former president between 2007 and 2011.

Prosecutors said they recently interrogated Lee Pal-seung over suspicions that he paid the money in exchange for his appointment as the chairman of Woori Finance Holdings, which was then controlled by the government. Lee Pal-seung took helm of the firm in June 2008, and headed it for two terms until 2013.

During a raid of Lee Pal-seung’s home, prosecutors found memos that said he delivered 800 million won to the former president’s elder brother Lee Sang-deuk in October 2007, and 1.45 billion won to Lee Sang-joo, an executive at Samsung Electronics and son-in-law of the former president, between 2008 and 2011.

The prosecution searched Lee Sang-joo’s home and office on Monday, and grilled him on Monday and Tuesday on how he received the money and whether the former president was involved.

Lee Pal-seung, a Korea University alumnus -- as is Lee Myung-bak -- was known to be among the four closest people to the former president in the financial sector.

The former head of Woori Investment and Securities took helm of the Seoul Philharmonic Orchestra in 2005 when the ex-president was the city’s mayor. He then served as a special adviser to Lee Myung-bak during his presidential election campaign in 2007.

The latest suspicions of bribery add to the number of corruption allegations against former President Lee involving his brother’s auto parts manufacturer DAS, the state spy agency and Samsung Group.

Prosecutors have been zeroing in on Lee Myung-bak over suspicions that he used DAS to run slush funds, that his presidential office received “special activities” funds from the National Intelligence Service, and that Samsung paid legal fees for DAS.

The prosecution is expected to summon Lee Myung-bak for questioning early next month.

By Kim So-hyun (sophie@heraldcorp.com)