An independent prosecutor Tuesday launched a criminal inquiry into fraud allegations against South Korea's next president Lee Myung-Bak, just six weeks before he is set to take office.
Lee, a former construction CEO who strongly denies wrongdoing, is the first president-elect from a business background and the first to face a criminal probe.
His inauguration appeared set to go ahead on February 25 regardless of the outcome of the investigation, given the time constraints.
But any finding that he was involved in a 2001 share manipulation scandal would weaken his authority and could damage his conservative party's prospects in the April general election.
In the December 19 presidential poll Lee won the biggest victory margin in the country's democratic history, despite the independent fraud probe authorised by parliamentary opponents two days beforehand.
State prosecutors in early December had cleared Lee of involvement in the fraud. The 66-year-old president-elect indicated Monday that he expects the independent counsel would also exonerate him.
"The prosecution has already conducted a thorough investigation and questioned those involved," he said. "I expect the independent counsel also to do a fair and good job."
Former high court chief judge Chung Ho-Young and five deputies opened an office in southern Seoul to kick off the investigation, his aides said.
It can last for up to 40 days -- February 24 -- but the counsel should announce whether the case is indictable before the 30th day on February 14.
"A criminal indictment by itself cannot block a president-elect from taking office," a constitutional court official told AFP on condition of anonymity.
"But a big debate would follow on whether a criminal trial should continue because an incumbent president is immune from prosecution (except for treason)."
The constitutional court ruled last week that the probe should go ahead despite a challenge from Lee's supporters. But it restricted the counsel's powers by refusing him permission to call witnesses without a warrant.
Some analysts believe the probe can lay suspicions to rest.
"Despite the prosecution's earlier probe, suspicions have remained widespread. The investigation can somehow help Lee Myung-Bak to make a fresh start and then run the country," Im Ji-Bong, a political science professor at Sogang University, told Yonhap news agency.
The case involves Lee's former business partner Kim Gyeong-Jun, whose trial for stock manipulation, embezzlement of 38 billion won (42 million dollars) and forgery began Monday.
Lee denies any knowledge of stock manipulation and says he was himself a victim of the fraud.
The independent counsel will also investigate whether Lee lied about his wealth and alleged ownership of real estate in an upmarket district of Seoul.