Arizona state trooper Edward Andersson, a 27-year-old veteran, noticed a rollover car on Interstate 10 west of Phoenix and stopped to investigate.
He was blocking off the scene of the wreck and placing flares when he was shot in his chest and right shoulder. Authorities believe the man who shot Andersson was driving the car that crashed.
The man then started slamming the officer's head into the pavement.
That's when the passing motorist stopped by. The trooper asked him for help.
"The trooper says, 'Please help me,' and asks the uninvolved third party for help," Col. Frank Milstead, director of the Arizona Department of Public Safety, said. "That person retreats back to his vehicle, removes his own weapon from the vehicle, confronts the suspect, giving him orders to stop assaulting the officer. The suspect refuses. The uninvolved third party fires, striking and killing the suspect."
Meanwhile, another motorist stopped at the scene and after witnessing what was going on, ran to the officer's vehicle and called for help.
According to a recording of the police radio exchange, he told a dispatcher: "Hello, officer down, officer down outside Tonopah. Come in, please. This is a civilian. He's shot on I-10 on the eastbound lane — sorry, westbound lane."
"He's in real bad shape. Please send air support, helicopter, please. There are also two civilians on — off — [the] road also laying [in] unknown condition," he continued.
The second motorist was identified as Brian Schober, from Scottsdale, Arizona.
"My concern was his life," he told NBC.
The brave driver who shot the assailant was identified only as a man who was traveling to California with his wife.
"My trooper would not be alive without his assistance," DPS Director Frank Milstead said.
Thanks for the thoughts and prayers this morning for our Trooper that was shot. Looks like he will be okay after some recovery @Arizona_DPS— Col. Frank Milstead (@frank_milstead) January 12, 2017
The good Samaritan isn't in any legal trouble, thankfully, for his help. Arizona has a "defense of third person" law that allows someone to use deadly force against another who is threatening or injuring a third person.
Investigators were trying to determine the cause of the accident as well as the incident that followed.
A woman who was believed to have been ejected from the vehicle was later determined to have died at the scene.
Banner and thumbnail credit: Reuters