In the past, the prosecutors’ office has often been accused of being obedient to the incumbent president and those close to him. It turned itself into a target of similar accusations again this week when it decided not to file criminal charges against any of those involved in the dubious land purchases in the outskirts of Seoul made for the construction of President Lee Myung-bak’s post-retirement residence.

What is now in store for the prosecutors’ office is the public humiliation of being sidelined should the National Assembly or an independent counsel start a new investigation into the case. The ruling and opposition parties share the opinion that a new investigation is needed to clear public suspicions.

The claim by critics that the prosecutors’ office proved its subservience to the president again may not be misplaced, given that its latest decision is also rejected by the ruling Saenuri Party. Rep. Lee Han-koo, floor leader of the ruling party, says he cannot trust the outcome of the prosecutorial investigation into an allegation that President Lee’s son breached the law on property transactions when he bought the land on behalf of his father and that he made an illicit gain from the purchase.

The prosecutors’ office, he says, made an “impudent” decision when it cleared the president’s son of criminal charges after receiving a written reply to its questionnaire, instead of summoning him for questioning, as it usually does. Otherwise, the son might have undergone a grueling interrogation, possibly lasting more than 10 hours.

Rep. Lee’s remark is an unmistakable indication that his party will not come to the president’s rescue, as it has often done in the past, if the National Assembly should decide to start an investigation of its own, or pursue an investigation by an independent counsel, into the case involving his son and some of his aides and secret service agents. Indeed, the floor leader says the National Assembly will have to start an investigation of its own or select an independent counsel if either is deemed necessary.

A prosecutorial investigation started when the Democratic United Party pressed charges against the president’s son and six others in October last year. The opposition party claimed that the president’s son breached the law on property transactions when he bought the land on behalf of his father and that he bought the land at a price 900,000 million won below its market value.

It is a criminal offense for a person to buy land in the name of someone else. The presidential office acknowledged that the land was purchased for the building of the president’s post-retirement residence.

But the prosecutors’ office cleared him of criminal charges, claiming that he did not break the law because he borrowed money and paid for the land and that he had intended to sell the land to his father. Maybe so. Still, it was far from open and aboveboard for the presidential family to exploit such a loophole.

Moreover, purchase financing was not so transparent. The president’s son offered a plot of land in his mother’s possession as collateral when he borrowed 600 million won from a bank. He also borrowed another 600 million won from one of his uncles at an annual interest rate of 5 percent. The prosecutors’ office did not explain where he got the millions of won needed for monthly interest payments. He is not thought to have a large income as he was a junior corporate employee.

Even more troublesome was the joint purchase of the plot of land for the construction of a residence and that for the construction of a building for a Presidential Security Service detail. The book value of the land for use by the president was reduced to below the market value and the difference was tapped by the Presidential Security Service.

The prosecutors’ office deserved to be discredited by the public when it said it had no evidence to believe the official in charge at the Presidential Security service had intended to benefit the president’s son at the expense of taxpayers. Still worse, it passed the buck to the Board of Audit and Inspection when it referred the case to the state watchdog.