A criminal investigation into a corruption scandal involving a shopping mall developer took a new turn when prosecutors summoned Park Young-joon, a former vice minister of knowledge economy and one of President Lee Myung-bak’s closest protgs, for questioning Wednesday.

An inquiry into Park’s potential involvement in the scandal followed the arrest of Choi See-joong, a former chairman of the Korea Communications Commission, who was often dubbed Lee’s political mentor. Choi is suspected of taking hundreds of millions of won from the “Pi City” developer building a large shopping mall in Seoul. Other people that are mentioned in connection with the bribery scandal include the president’s older brother, Rep. Lee Sang-deuk.

In the past, Park has allegedly been involved in several scandals, including the manipulation of the share prices of a company investing in diamond mining in Cameroon and the surveillance of civilians by government officials. But he avoided prosecution each time, either because the evidence against him was not strong enough or because prosecutors were enfeebled in the presence of a powerful figure, as their detractors alledge.

Now Park is accused of taking a huge amount of money from the developer and laundering it through the bank accounts of a businessman based in Pohang, who was a member of Rep. Lee’s supporter group. Park was an aide to Rep. Lee before he started to work for President Lee when he was Seoul mayor.

Incidentally, the Pohang-based businessman heads a supplier to POSCO, whose subsidiary is contracted to build the “Pi City” shopping mall. The turnover of the company, which was at 2.7 billion won in 2007, increased to 10 billion won in 2008 when it was selected as a supplier to POSCO and 22.6 billion won in 2010. Rumors had it that Rep. Lee exercised great influence on POSCO.

With the president slipping fast into lame-duck status in his final year in office, it is yet to be seen whether or not the prosecutors’ office will bring criminal charges against Park this time. Also of great concern to the public is who the prosecutors’ office will summon next time as it widens its investigation into the corruption scandal involving the president’s men.

A senior prosecutor has been quoted as saying that one of the cases under investigation is related to many others and that his office is determined to follow all the leads to enforce criminal justice. It should.