Prosecutors arrested Park Young-joon, a former vice minister of knowledge economy, and took him into custody Monday. The charges against him were influence-peddling and taking 100 million won in bribes from the developer of a Seoul shopping mall.

His arrest followed the issuance of a warrant by a judge at a Seoul district court, who was quoted as saying he was considered a flight risk and that he could try to destroy evidence. Before being taken into custody, Park told reporters that he had nothing special to say and that he was sorry.

Park, one of President Lee Myung-bak’s most trusted proteges, is often called the king’s man. He was charged with taking 100 million won from a company building the Picity shopping mall. The developer had allegedly wanted him to exercise his influence in obtaining a building permit when Lee was Seoul mayor.

Park’s arrest followed that of Choi See-joong, a former chairman of the Korea Communications Commission and a “political mentor” for Lee. Choi is also suspected of taking a huge sum of money from the Picity developer. Park and Choi were members of Lee’s six-man inner circle.

Suspicions against Park were not limited to the 100 million won in bribes. Prosecutors, who had looked into bank accounts held by his relatives, found billions of won deposited in an account held by his older brother. They suspect that the account is really Park’s, not his brother’s, and that he borrowed his brother’s name when he opened it.

Park had been a “Teflon” suspect until he was arrested on Monday. He had in the past managed to avoid criminal offenses sticking. He had been suspected of being entertained by a businessman seeking favors and involved in the manipulation of stock prices of a company mining diamonds in Cameroon. His name had also been mentioned in connection with the illegal surveillance of civilians by government officials. Each time he had escaped criminal charges, making people wonder if the prosecutors were incompetent, indulgent or cowed.

Now their competence and honor is at stake, the prosecutors will have to leave no stone unturned in their investigation into the bribery case involving Lee’s confidants. They may have to expand their investigation, given the allegations that others close to Lee were also involved in making the decision to issue a building permit to the developer.