PORTLAND — A judge is set to deliver his verdict in the trial of a Portland man who strangled his girlfriend, cut off her head and set her body afire.

Prosecutors and defense lawyers clashed over the mental state of 29-year-old Chad Gurney, who’s using an insanity defense. The defense contends Gurney was delusional at the time of the killing, but the prosecutor contends Gurney was simply angry because his girlfriend had slept with someone else.

Neither side is questioning that Gurney killed 18-year-old Zoe Sarnacki in his apartment on May 25, 2009.

Justice Roland Cole, who heard the case without a jury, plans to deliver his verdict today in Cumberland County Superior Court.