CLEVELAND (AP) — A man who Ohio authorities say stabbed woman 200 times with a sushi knife before decapitating her has pleaded guilty to an aggravated murder charge and been sentenced to life in prison with no chance of parole for 25 years.

Cleveland.com reports 34-year-old Jiansen Liang also pleaded guilty Monday to a corpse abuse charge in 33-year-old Qihong Chen’s 2017 slaying in suburban Cleveland.

Authorities say the Chinese national went to Cleveland police in July 2017, confessing to the slaying. Chen’s body was found in her apartment in suburban Fairview Park.

Liang told psychiatrists he attacked Chen after having visions of her turning into a monster.

Prosecutors say they believe Chen and Liang were friends, but Liang wanted more.

Defense attorney Richard Drucker said Liang is bipolar with a low IQ.