A suspect accused of striking ruling People Power Party(PPP) Rep. Bae Hyun-jin on the head with a blunt object in southern Seoul on Thursday testified to the police that the attack was not premeditated.

According to the police on Friday, the 15-year-old suspect told investigators at the Seoul Gangnam Police Station that he had been outside for about two hours before running into the lawmaker by chance.

He claimed that he had been awaiting hospitalization at a secured ward for aggravated symptoms of depression and that he had regularly carried the stone used in the attack.

After apprehending the suspect at the scene of crime, the police have been focusing their investigation on the criminal motive through analyses of his mobile phone, social media activity and whereabouts leading up to the attack.

According to people acquainted with the suspect, he had run into problems at school since last year, attending in-school counseling and receiving treatment, while a hospital reportedly diagnosed him with bipolar disorder.

The police forcibly admitted the teenager to a psychiatric ward under emergency hospitalization early Friday, in consideration of his age and current health condition.