A 23-year-old male university student was arrested Wednesday on suspicion of killing a doctor at her apartment in Higashine, Yamagata Prefecture, last month, local police said.

Hiroki Kato, a fourth-year student at Yamagata University, is suspected of breaking into the apartment of ophthalmologist Chiemi Yaguchi, 50, and bludgeoning her to death early on May 19.

The police declined to say at a news conference whether Kato has admitted to the allegations. They said that the two, living in different municipalities about 20 kilometers away from each other, appear to have had no connection before the incident.

A bloodied golf club was discovered at the scene of the murder.

According to investigative sources, security cameras captured images of a person in dark clothes — believed to be Kato — entering and leaving Yaguchi's room a few times before she was found dead.

On May 18, Yaguchi went to work at an eye clinic she headed in the prefecture and later attended an employee's welcome party in the evening, an official of the clinic said. She went home after the event and talked on the phone with a staffer at around 10:45 p.m. She had the next day off.

Yaguchi's body was discovered by her younger brother, who visited her apartment on the afternoon of May 19.

Kato, who is a student in Yamagata University's faculty of humanities, was not listed as a patient at the doctor's clinic, which closed late last month.