Kim, 29, is suspected of stabbing a 21-year-old man to death in an Internet cafe in Seoul's Gangseo ward, on Oct. 14. Kim has confessed to killing the part-time worker at the cafe, saying that he got angry that the worker didn't clean the table as Kim had asked.

Police publicly disclosed Kim's identity after an internal committee decided to do so given the seriousness of the crime and the public interest.

Justice Minister Park Sang-ki instructed officials to speed up Kim's evaluation as the case drew attention from media and public after his family brought up his mental illness.

A petition has been filed at the presidential office's website calling for a stern punishment for Kim and that the argument of mental disease should be disregarded.

Under the criminal law, insanity defense or a plea for leniency on grounds of being mentally unfit can mitigate the sentence by up to half the term.

"In light of the result on the psychiatric evaluation, it is ascertained that Kim had been treated for depression, but he was not having a mental breakdown, and was not mentally unfit, meaning he was aware of his actions," the ministry said in a statement.

Kim will be transferred back to the detention center in Seoul and police plan to soon refer the case to the prosecution when they wrap up the probe, the ministry said. (Yonhap)