In a widening sex-for-favors scandal, Vice Justice Minister Kim Hak-ui tendered a letter of resignation on Thursday. While denying being involved in the scandal, Kim said his name being mentioned in connection with it made it impossible for him to continue to do his work as a vice minister.

But his resignation reaffirmed that background checks by the Park Geun-hye administration on those selected for top public posts were seriously flawed. The presidential office, though informed of his alleged involvement, concluded the allegation was groundless and proceeded with his appointment to the vice ministerial post.

His departure followed that of Hwang Chul-joo, a vice chairman of the Korea Venture Association, who had been selected to head the Small and Medium Business Administration. Hwang withdrew from the post last week because of a rule requiring high public officeholders to dispose their equities if they related to their new duties. He did not want to part with his holdings in a venture amounting to 70 billion won. It was disclosed that he had not received a detailed explanation about the rule.

Police had long been looking into an allegation that a construction company executive arranged banquets and sexual services for former and incumbent government officials and other influential figures in return for influence when a daily recently reported the newly appointed vice justice minister was involved in the scandal.

An investigation started when a woman pressed charges of rape and extortion against the company executive last year. She also told police that a number of CD-ROMs showing high-ranking officials having sex with women had been found in a car she had lent to him. More than 10 women, including housewives and graduate school students, were allegedly employed to provide sexual services in a remote villa in Gangwon Province.

Allegations were made that the company executive used the CD-ROMs to blackmail the officials for business favors. Police said they were in the process of confirming the allegations.

The provision of sexual services in return for business favors is not a simple, innocuous scandal. It is a criminal act into which police investigators will have to delve deeply. Quite a few already voice concern that the investigation into the scandal, which has come in the early weeks of the new administration, may be scaled down.

But all those criminal suspects must be brought to justice. As President Park Geun-hye noted earlier, public trust in the entire officialdom will plummet even if one single public servant is found to have been involved in a serious corruption case.