TONOPAH, Ariz. (KSAZ) - An Arizona state trooper stopped to help at a car wreck along a remote highway Thursday when he was shot and wounded in an ambush by a man who was bashing the officer's head against the pavement until a passing driver shot him to death, authorities said.
The trooper suffered a severe wound to his shoulder and upper chest but he is expected to recover at a hospital.
DPS has identified the 27-year state trooper as Edward Andersson.
"My trooper would not be alive without his assistance," Department of Public Safety Director Frank Milstead said of the good Samaritan who stopped.
The drama unfolded at an early morning rollover wreck on Interstate 10 in the desert west of Phoenix where a woman was ejected and killed. Authorities believe the man who shot the officer was driving the car that crashed.
Officials said they were trying to determine exactly what happened and that the investigation faced major hurdles with the trooper seriously injured and two of the others involved dead.
A separate driver reported gunfire and a trooper was responding to that call when he spotted the wreck and stopped, Milstead and DPS Capt. Damon Cecil said.
The officer was putting out flares when the suspect opened fire and then physically attacked Andersson, Milstead said. Both Milstead and Cecil said Anderson was ambushed.
The man was on top of the officer and "getting the better of him," slamming Andersson's head against the pavement, Milstead said. That's when the passing driver showed up and asked if the trooper needed help.
He said yes, and the passer-by went back to his vehicle, got his gun and told the suspect to stop the attack, Milstead said. When he didn't, the driver shot him.
Investigators were trying to determine how the rollover happened and whether the suspect was involved with the initial report of gunshots, officials said. Investigators plan to speak with the person who made that call.
Milstead said he feared the worst when he headed to the hospital to check on Anderson
"He's incredibly fortunate to be here with us today," the director said.
Westbound Interstate 10 was closed most of the morning, and traffic heading for California and western Arizona was detoured to other highways.
Please pray for quick recovery of our @Arizona_DPS officer shot this morning. Reminds us women/men in blue put lives on the line everyday.— Doug Ducey (@dougducey) January 12, 2017
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
CLOSED: I-10 westbound at milepost 89 due to police activity. Expect an extended closure. pic.twitter.com/uLHuvpNcjZ— Arizona DOT (@ArizonaDOT) January 12, 2017
I-10 update: WB closure now in place at 411th Ave. Detour: 411th SB, Salome WB, Courthouse WB, Harquahala Valley NB to I-10. Expect delays. pic.twitter.com/qfLcEQDQLD— Arizona DOT (@ArizonaDOT) January 12, 2017
I-10 update #2: A detour on local roads is being set up near Tonopah, but expect delays. Also consider these alternate routes. pic.twitter.com/miB2N0JFa9— Arizona DOT (@ArizonaDOT) January 12, 2017
The Associated Press contributed to this report.