DEVILS LAKE (AP) - A psychologist testified Monday that Aron Nichols told him he was at the home of Donald and Alice Willey but cannot remember what happened there.

Dr. Stephen Podrygula of Minot testified that Nichols is paranoid and suffers from delusions and personality disorders. Podrygula said he sometimes feared for his own safety during his sessions with Nichols.

"I felt this man could go off at any minute at anyone," Podrygula said.

Defense attorney Robert Martin told jurors in his opening statements Monday that they should consider Nichols' mental condition at the time of the killings.

Nichols is charged with murder in the deaths of 70-year-old Donald Willey and his 67-year-old wife, Alice, whose bodies were found in their burned home near Sykeston.

His fiancee, Tamara Sorenson, is charged with being an accomplice in the deaths.

Authorities said the couple were shot to death, and their home was burned to cover up the crime.

Podrygula testified that he believes Nichols was suffering from an extreme emotional disturbance at the time of the Willeys' deaths.

Nichols' paranoia could have played a role, his overreaction to something unexpected happening or his self-righteous and protective nature all could have been factors, Podrygula said.

Prosecutors challenged those theories. Assistant Attorney General Jonathan Byers asked Podrygula if he would be surprised to hear that Nichols showed no reaction when his best friend gave testimony that damaged his defense.

"That shows he has some control," Podrygula said.

Correctional officers described Nichols as a powder keg ready to explode, and said he had significant discipline problems while incarcerated pending trial, Podrygula said.

The prosecution rested its case earlier in the day after calling 79 witnesses to testify over nine days. The final prosecution witness was a handwriting expert, David Lybeck. He said Sorenson likely wrote out the map and directions to the Willey home. Defense attorneys suggested handwriting inconsistencies, but Lybeck maintained it was highly likely Sorenson wrote the notes.