A 24-year-old police officer has been shot dead while investigating a domestic violence case in Flagstaff, Arizona.
Flagstaff Police Department said Tyler Stewart was shot several times after responding to reports of the confrontation.
The suspect, identified as 28-year-old Robert W Smith, then turned the gun on himself.
He is reported to have died at the scene.
Local media said Mr Stewart, who had been an officer with the Flagstaff Police Department for less than a year, died of his wounds in hospital a short time later.
Several sources say he had been shot in the face.
“This is an enormous tragedy for our department and the family of our officer,” Flagstaff Police Chief Kevin Treadway said.
“We are a very close knit organisation, and know that all members of the Flagstaff Police Department are grieving at this time.
“With that being said, all of the men and women of the Flagstaff Police Department extend our prayers and condolences to the family of our Officer Tyler Stewart.”
Mayor Jerry Nabours said: “It is heartbreaking to lose one of our officers. We collectively mourn for his family and the entire department”.
According to local newspaper the Arizona Daily Sun, Mr Stewart is just the second officer in the history of the Flagstaff Police Department to die in the line of duty.
The first was Officer Jeff Moritz, who was shot dead in 2000.
A candlelit vigil was due to be held outside the Flagstaff Police Department on Sunday evening.