A man shot and killed himself Wednesday inside a Mesa restaurant after shooting another man who was taken to a hospital with life-threatening injuries, police said.

Joseph Papineau, 51, died in the shooting at Desert Peaks Pizza and Grill, 5943 E. McKellips, and Jason Zuchowski, 45, was injured, according to authorities.

Mesa police were called to the restaurant about 4:50 p.m. Wednesday, Nov. 2, and found both men on the ground inside with gunshot wounds.

A preliminary investigation revealed that Zuchowski and his girlfriend arrived at the restaurant and found Papineau inside. According to police, Papineau was the woman’s ex-boyfriend.

The couple sat at the opposite end of the bar from Papineau, police said, adding that an argument eventually began between the two men.

Papineau left his seat at the bar, walked over to Zuchowski and shot him before shooting himself, according to the preliminary police report.

Officers administered first aid to the men until Mesa Fire and Medical personnel arrived. The men were taken to a hospital, police said.

Papineau was pronounced dead, and Zuchowski was taken into surgery with life-threatening injuries. He remains in the hospital, police said Thursday morning.

Authorities said the incident appears to be an isolated case, and police are not looking for anyone else. The  investigation continues.