A prosecutor-turned-lawyer appointed to head the National Office of Investigation offered to resign Saturday, just a day ahead of assuming his post, amid a bullying controversy involving his son at school.

Chung Sun-sin, appointed as the new chief the previous day, found himself in hot water after it was belatedly revealed that his son had verbally abused one of his peers for eight months in high school and was ordered to transfer schools.

"Many have been concerned due to my son's problem, and I came to the conclusion that I cannot take on such a grave responsibility as the chief of the National Office of Investigation with this flaw," he said in a release.

"I ask for forgiveness from the victim and his parents once again for what my son did," he added.

Although Chung was formally appointed by President Yoon Suk Yeol, he will be stepping down by withdrawing his application for the post, as his term has not yet officially begun.

Chung's decision comes amid mounting pressure from the public and politicians despite his apology made earlier in the day.

With Chung's resignation, the post will be left vacant for the time, as the term of Nam Gu-jun expires Saturday.

Chung had worked for the prosecution for about 20 years and served as the head of the Institute of Justice's branch in Yongin, 40 kilometers south of Seoul. He was recommended by National Police Agency Commissioner General Yoon Hee-keun. (Yonhap)