The 30-year-old man accused of assaulting and raping a woman on a hiking trail in Seoul has said he used two brass knuckles when beating her, police officials said Friday.

The suspect surnamed Choi was put under police custody the previous day shortly after he allegedly beat and raped the victim he randomly picked on a hillside trail in the Sillim district in southwestern Seoul at 12:10 p.m.

The woman was immediately transported to a hospital but remains unconscious.

The suspect told police the previous day that he "wore brass knuckles on both hands and assaulted the victim," police officials said.

He also admitted to assault and rape charges, the officials said, quoting him as saying, "I committed the crime because I wanted to rape."

According to officials, Choi arrived at the hillside park about an hour before his crime and looked for a victim. "I chose the place for a crime because I went there often and knew it has no CCTV cameras," police quoted Choi as saying.

Alcohol and drug tests conducted on him the previous day were negative.

Police sought a warrant Friday to formally arrest him on charges of rape and assault, while an inspection is under way into his medical and mobile phone records to determine whether he has medical history of mental illness. (Yonhap)