Divine providence, an armed passerby said, enabled him to save an Arizona state trooper from an attack on a remote highway early last Thursday. In a news conference held on Monday, Col. Frank Milstead, Arizona’s Department of Public Safety director, described the story — the most accurate version of it, as Milstead said he knew then — of a bizarre and violent scene that unfolded in the predawn desert on Jan. 12.

Arizona Department of Public Safety trooper Edward Andersson was responding to an emergency call on Interstate-10, as The Washington Post reported Friday, when he was shot and beaten.

A passing driver had spotted a “man in the roadway with a handgun,” Milstead said at Monday’s news conference. The driver heard a loud bang, and his car began to lose power. His vehicle, the driver realized, had been shot, and he phoned the police.

Police identified the suspect in the roadway as Leonard Pennelas-Escobar, 37, of Mexico. He was known to use methamphetamine but had no criminal background; Pennelas-Escobar may have at one time been employed in Mexico as a federal police officer, Milstead said. Investigators said that Pennelas-Escobar was traveling in the United States illegally when the vehicle he was driving rolled over on I-10.

It was unclear on Monday why the car crashed. Based on the tire markings, investigators believe the car, which Pennelas-Escobar likely drove, had been traveling at high speeds; it may have spun out of control. The force of the crash also expelled the vehicle’s other occupant, 23-year-old Vanessa Monique Lopez-Ruiz of Phoenix. Lopez-Ruiz, who was in a romantic relationship with Pennelas-Escobar, later died from her blunt trauma injuries.

Other motorists on the interstate called the police to say they witnessed a man dragging a female body out of the road. Andersson, who has not yet been formally interviewed but spoke to investigators while in the hospital and on painkillers, spotted a “Hispanic male with a female in his arms,” Milstead said. The pair had crouched on the right shoulder of the highway.

Andersson exited his police car, set out road flares and approached to help the injured man and woman. Pennelas-Escobar exclaimed something in Spanish, which Andersson could not make out or understand.

It was then that the suspect shot Andersson, once, with a 9 mm pistol, Milstead said.

The bullet entered Andersson’s upper right shoulder and exited through his right torso. The trooper’s arm went numb. The Arizona safety director did not know why the suspect fired at Andersson. But Milstead suggested that it was possible Pennelas-Escobar became distraught and angry after the collision, or he was hallucinating while on methamphetamine; agitation, paranoia, psychosis and other pharmacological effects of methamphetamine use have been linked to violence.

The two men engaged in a physical fight. A motorist, driving with his fiancee, was traveling toward California behind Andersson when he spotted the fight. As he approached the grappling pair, the driver slowed to about 20 or 30 mph. He saw a “Hispanic male straddling the trooper, taking big blows at him,” said Milstead, gesturing with his fists, “trying to bang his head into the ground.” The motorist stopped his car.

Milstead described the man, who has so far declined to be identified or publicly interviewed, as a “very humble, spiritual guy” and a “good Samaritan.” The public safety director spoke to the motorist by phone on Saturday. “I have never talked to anybody like him before,” Milstead said.

The motorist retrieved a 9 mm handgun from the center console of his car. While his fiancee dialed the police, he approached Andersson and the suspect. The motorist told the suspect to stop beating the police officer. Pennelas-Escobar, Milstead said, responded with profanity.

The motorist circled around the pair to find the clearest line of sight to the suspect. He fired at least two bullets at Pennelas-Escobar, temporarily incapacitating him. The armed motorist and another passerby began to tend to Andersson’s wounds, radioing for emergency help.

Despite the gunshot wounds, Pennelas-Escobar stood up and attempted to assault Andersson again.

“The good Samaritan fires another round, striking the suspect in the head, mortally wounding him and ending the fight,” Milstead said. The armed motorist had no professional experience with weapons, although, Milstead said, the man practiced shooting three or four times a year alongside military or law enforcement friends.

“He knows he did the right thing.” Milstead said. “He is trying to reconcile that in his mind, which is difficult to take a life even when you know it’s the right thing to do.”

There was no suspected connection between Pennelas-Escobar and the civilian. “He believes that God put him there that morning,” Milstead said, “so he could save Trooper Andersson’s life.” As of Monday, Andersson was recovering at home after being released from an Arizona hospital.

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