The prosecution is facing mounting pressure to expand its probe into the savings bank lobbying scandal involving President Lee Myung-bak’s associates, upon widening suspicion that the kickbacks were used to support Lee during the 2007 presidential election.

All eyes are now on Lee Sang-deuk, elder brother of President Lee, who is claimed to have bagged up to 3.8 billion won ($3.3 mil.) in total from several ailing savings banks around 2007, when the younger Lee was campaigning for the presidency.

The prosecutors were set to seek an arrest warrant for Lee Sang-deuk Friday on charges of accepting 300 million won from Lim Suk, chairman of Solomon Savings Bank, and around 600 million won from Kim Chan-kyong, chairman of Mirae Mutual Savings Bank, in 2007.

According to Hankyoreh, the amount from Kim Chan-kyong could reach up to 3 billion won, according to testimonies from a bank official who was not identified.

Lee is also suspected of handing over some or all of the money he received from Lim to former lawmaker Kwon Oh-eul, who was the campaign manager for President Lee.

Prosecutors plan to question Kwon over the allegation, but Kwon is unlikely to face charges if he had not been aware of the source of the funds.

On Thursday, Rep. Chung Doo-un of the ruling Saenuri Party was also summoned to explain whether he had taken more than 30 million won from Lim in exchange for arranging the meeting between Lee Sang-deuk and Lim. Chung fervently denied the allegation.

As he left the prosecution building late at night, the three-term lawmaker and former right-hand man of President Lee claimed he had been maltreated by the government.

“Let’s say the summons was a minor glitch to avoid an even bigger scandal,” he said.

He, however, did not comment on whether the money was linked to any slush funds for the presidential campaign.

Another former ruling party member also faced new allegations in the burgeoning scandal.

Kim Deog-ryong, a former ruling party heavyweight, allegedly introduced Kim Chan-kyong to Lee, according to local news reports.

Lee Sang-deuk reportedly admitted to some of the allegations at the Monday summons and is also rumored to have been involved in more than seven other irregularities.

Opposition forces, meanwhile, urged the prosecution to launch an official investigation into the alleged slush fund for Lee Myung-bak in 2007.

“Now that the in-and-outs of the dirty money has been verified, the prosecutors must thoroughly investigate the case. If the investigation shows a poor result, people will seek to protest the prosecution,” said Kim Hyun, spokeswoman of the main opposition United Democratic Party.

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