The prosecution’s probe into a bank-lobbying scandal is set to implicate a key opposition leader, igniting a political firestorm with the presidential election just six months away.

Local media reported Friday that Rep. Park Jie-won, floor leader of the main opposition Democratic United Party, is under investigation on suspicions that he received money from a jailed banker in exchange for peddling influence. 

Rep. Chung Doo-un of the ruling Saenuri Party is also suspected of similar charges, they said.

Officials at the central investigation department of the Supreme Prosecutor’s Office, who are leading the probe, didn’t confirm the reports. But Yonhap News quoted an unidentified official there as saying: “We say we are ‘investigating’ (someone), because we have substantial reasons to say so, more than just rumors and tip-offs.”

The probe has already implicated Lee Sang-deuk, a former ruling party lawmaker and elder brother of President Lee Myung-bak, considered the most influential person in the incumbent administration.

The older Lee will be questioned on July 3 on suspicions that he received kickbacks from ailing savings banks seeking to evade a forced shutdown by the regulators.

The former six-term lawmaker is believed to have received more than 300 million won ($256,000) from Lim Suk, chairman of Solomon Savings Bank and Kim Chan-kyong, chairman of Mirae Mutual Savings Bank, from 2008 to 2010. The two institutions survived from the government’s restructuring plan on the savings bank in September last year but were ordered on business suspension on May 7 due to a lack of financial stability.

Both Lee and Kim have been arrested and indicted over embezzlement charges.

Lee is also suspected of having received another 400 million won from the management of Prime Savings Bank that was ordered to shut down last year. The bribes are believed to have been hidden under Lee’s secretary’s bank account, which was found earlier this year during an investigation into a separate case.

Investigators are also determined to question about Lee’s allegedly inappropriate liaison with Lee Kuk-chul, chairman of SLS Group, who claims to have handed hundreds of millions of won to Sang-deuk to save his company from the workout process.

Senior Lee was also claimed to have induced the management of Pohang University of Science and Technology to invest over 50 billion won to now-defunct Busan Savings Bank to inflict financial loss to the school. Lee is suspected to have bridged the business deal up on request from the financial institution in exchange for money.

Lee’s office said all claims are not true and that Lee will sincerely verify all allegations to the prosecutors.

The probe is now targeting other political powerhouses.

The prosecutors have reportedly secured evidence that Lim has splashed up to 300 million each to Rep. Park, Rep. Chung and several others.

Park said he had met Lim once but has not received a penny from him. Chung, once a close aide to the president, admitted that he had introduced Lim to Lee Sang-deuk in 2007 but has never received any sponsorship from the scandal-ridden businessman.

All eyes are now on whether Lee will be indicted. Still, regardless of the outcome his being summoned has already dealt a huge blow to the president already staggering over slews of scandals involving his close allies.

Choi See-joong, former head of Korea Communications Commission known as the mentor to the president; former Vice Knowledge Economy Minister Park Young-joon; former Vice Culture Minister Shin Jae-min; and former presidential spokesperson Kim Du-woo have been arrested, indicted and some convicted, over various corruption charges.

“If Sang-deuk gets indicted, it will be the pinnacle of the Lee government’s nepotism. It will also accelerate the lame duck phenomenon inside the crumbling circles,” said an observer.

The ruling Saenuri sought to disassociate itself from the Lee scandals.

The party, which practically runs under its former chairwoman and Lee Myung-bak’s political rival Park Geun-hye, called for a thorough investigation. “We will be more objective and tougher to the irregularities of the current administration,” a party official was quoted as saying to Chosun Ilbo newspaper.

The opposition cried foul against the conservative government.

“This should be the start of an effort to swipe out all the corruption perpetrators. People ask for responsibility of the government for rows of scandals,” the DUP said in a press release.

By Bae Ji-sook (baejisook@heraldcorp.com)