PORTLAND — A Superior Court judge will rule at a court appearance Friday morning on whether Chad Gurney is guilty of murder.

Gurney, 29, is charged with murdering Zoe Sarnacki, 18, of Portland on May 25, 2009.

Gurney has pleaded not guilty by reason of mental disease or defect.

Justice Roland Cole will decide whether Gurney understood the wrongfulness of his actions when he strangled then decapitated Sarnacki at his Cumberland Avenue apartment before setting the apartment on fire.

If he is guilty, he will go to prison for many years. If he is found not criminally responsible, then he would be sent to a state psychiatric institution.

The two-week bench trial ended Jan. 20 with Cole saying he would issue a verdict later. There is no jury. The verdict is scheduled to be delivered at 9 a.m. Friday at Cumberland County Superior Court in Portland.