FORT COLLINS, Colo. — A northern Colorado man who was convicted of killing his 75-year-old neighbor in June 2015 has been sentenced to life in prison without the possibility of parole.

The Reporter-Herald reports 39-year-old Eric Gray of Loveland was sentenced Thursday shortly after a jury convicted him of first-degree murder in the death of Gerald Donovan, who was shot with an AK-47 rifle.

The defense called witnesses who testified that Gray’s mental illness and paranoia contributed to the shooting. A judge had found him competent to stand trial after a mental health evaluation.

During closing statements on Wednesday, Deputy District Attorney Jenny Ellison reminded jurors a psychiatrist testified that despite Gray’s delusions, he was still capable of making decisions and that he intended to kill Donovan.