A patient’s delusional disorder caused the patient to kill a psychiatrist at Kangbuk Samsung Hospital, police have concluded.

The Jongno Police Station in Seoul on Wednesday announced the results of the investigation on the suspect. “During the probe, the suspect repeated incomprehensible statements. After analyzing his past medical records, we have concluded that his delusions appear to have prompted him to commit the crime,” a police officer said.

Earlier, the police raided Kangbuk Samsung Hospital, the National Health Insurance Service, and the suspect’s home to secure the suspect’s medical records, a mobile phone, and a laptop.

However, the police failed to unlock the suspect’s mobile phone and discover evidence to identify the motive or plans for the crime.

Even though the suspect admitted killing the doctor, his statements have been incoherent about the motive of the crime, according to the police. The police quoted the suspect as saying that the patient was “arguing with the doctor over a bomb inside his head.”

“The suspect said ‘he asked the doctor to help him get rid of it, but the doctor called security instead,’” the police said.

The suspect is accused of stabbing the psychiatrist Lim Se-won to death during a consultation at the hospital’s psychiatrist department at around 5:40 p.m. on Dec. 31.

After wrapping up the probe, the police referred the suspect to prosecutors for indictment on Wednesday morning.