Former President Lee Myung-bak is being pushed into an increasingly tight corner as authorities delve deeper into allegations surrounding previous administrations. 

On Wednesday, investigators looking into allegations surrounding auto parts maker DAS raided the office of another parts maker, IM, and homes of an undisclosed number of company’s officials.

Lee’s eldest brother Lee Sang-eun is the official majority shareholder of DAS, but it has been alleged the former president is the real owner of the company. The elder Lee is also the majority owner of IM.

DAS is suspected of operating a 12 billion won ($11.2 million) slush fund under dozens of borrowed names. It has also been alleged that state agencies helped DAS recoup a 14 billion won investment in an investment advisory firm set up by a one-time business partner of the former president during Lee’s presidency.

The raid on IM comes less than a week after the prosecution raided DAS and other locations linked to individuals implicated in the case.

Meanwhile, an unrelated investigation has been turning up evidence implicating Lee Myung-bak in alleged misuse of the National Intelligence Service budget.

The investigation was launched after the NIS reform committee alleged that NIS funds were funneled into Cheong Wa Dae during former President Park Geun-hye’s term. The investigation has since led to the arrest of former NIS chiefs Nam Jae-joon and Lee Byung-ki.

While Lee Myung-bak rejects the allegations as groundless, two of his former aides -- Kim Jin-mo and Kim Paik-joon -- were arrested in connection with the case Wednesday.

Having served as an aide for Lee Myung-bak for over 40 years, Kim Paik-joon has sometimes been referred to as the former president’s butler. He served as senior secretary for administrative affairs to Lee between 2008 and 2012. Kim Jin-mo served as a civil affairs secretary from 2009 to 2011.

Kim Paik-joon is accused of receiving 400 million won in total from the NIS in 2008 and 2010, according to prosecutors.

He denies the allegations, but media reports claiming that former NIS chief Won Sei-hoon, under arrest in a separate case involving alleged political meddling by the NIS, confessed to handing over 200 million won to Kim have emerged. According to reports citing unnamed judiciary sources, Won told prosecutors that he ordered the money to be handed over at Kim’s request in 2010.

The investigators are said to have secured a similar testimony from Kim Ju-seong, a former Kolon Group official who headed the NIS’ coordination department under Lee.

According to reports, Kim Ju-seong told investigators that he first received request for money in 2008, and similar requests continued despite his raising concerns in a one-on-one meeting with Lee.

As for Kim Jin-mo, he is accused of using 50 million won of NIS funds to silence controversy surrounding civilians unlawfully surveilled by the Lee Myung-bak administration.

By Choi He-suk (cheesuk@heraldcorp.com)