TUCSON, Ariz. (AP) — Closing arguments are scheduled for Monday in the trial of a former University of Arizona graduate student accused of killing a professor on campus two years ago.

Murad Dervish, 48, faces seven felony charges including first degree murder in the death of Thomas Meixner, 52, who was shot nine times near his office and was pronounced dead at a Tucson hospital.

Defense attorney Leo Masursky told jurors that the killing wasn’t premeditated and that Dervish is “guilty except insane to second-degree murder,” an insanity defense.

Pima County prosecutors said Dervish planned the shooting and knew what he was doing.

Meixner headed the university’s Department of Hydrology and Atmospheric Sciences and was an expert on desert water issues.

Dervish was in the master’s degree program in atmospheric sciences, which is within the Department of Hydrology and Atmospheric Sciences.

Authorities said Dervish was banned from the school in January 2022 and later expelled for ongoing issues with professors after he received a bad grade.

According to a criminal complaint, a flyer with a photograph of Dervish had been circulated to university staff in February 2022 with instructions to call 911 if he ever entered the John W. Harshbarger Building, which houses the hydrology department.

The complaint also said Dervish was barred from being on school property and he had been the subject of several reports of harassment and threats to staff members working at Harshbarger.

Witnesses said Dervish was wearing a surgical mask and baseball cap as a disguise when he showed up outside Meixner’s office on the afternoon of Oct. 5, 2022, and shot the professor.

Dervish was arrested after Arizona state troopers stopped his car on a highway more than 120 miles (193 kilometers) northwest of Tucson.

Authorities said a loaded 9 mm handgun was found in the vehicle and that the ammunition was consistent with the shell casings found at the shooting scene.