A trainee prosecutor was found to have performed sexual acts with a suspect in the office and later had sexual intercourse with her at a motel, prosecution officials said Thursday, leading to concerns the incident could deal another blow to the scandal-ridden prosecution.

Inspectors at the Supreme Public Prosecutors' Office have launched an inspection to determine the details of the incident, the officials said.

"We are conducting an inspection into a law school graduate who is currently working as a trainee prosecutor at the Seoul Eastern District Prosecutors' Office," said Lee Jun-ho, chief of the inspection team.

According to the officials, the 30-year-old trainee, whose name was withheld, was found to have performed sexual acts in the office with a suspect in her 40s while questioning her on suspicion of theft and other crimes earlier this month.

A few days later, he took her to a nearby motel where they had sexual intercourse, they said.

The trainee reportedly told officials at the Seoul Eastern District Prosecutors' Office during an internal inspection that the sexual intercourse took place under mutual consent.

The suspect informed her lawyer about the incident, who in turn reported it to the prosecutor in charge of the trainee's training on Tuesday.

Inspectors at the Supreme Public Prosecutors' Office said they plan to question the trainee over whether he forced the suspect into having sexual intercourse with him or demanded it in return for favors in investigating the allegations against her.

The revelation comes only days after a ranking Seoul prosecutor was formally detained on charges of receiving a total of nearly 900 million won ($826,000) from Cho Hee-pal, the mastermind of South Korea's biggest-ever pyramid scheme, and the Eugene Group, a mid-sized conglomerate, in exchange for influence peddling. (Yonhap News)