Josh Polos watched in disbelief Monday morning as the gunman shot the wounded man, already helpless on the ground, in the head.

Then the shooter turned to Polos and looked him full in the face.

"I thought for sure he'd shoot me," Polos said. "But thank God, he got in the car and drove away."

Polos had just stopped to fill up his work vehicle Monday morning at a Holiday gas station in Arden Hills when, from 20 feet away, he saw a sedan pull up to the station and the driver get out and shoot dead his passenger outside the vehicle. Then the driver sped away, he said, running over the victim as he left.

"It was so surreal," said Polos, a flooring installer who was on his way to a job laying carpet. "You'd think that you'd run but I just stood there, frozen like a deer in headlights."

No arrests had been made late Monday night, but Ramsey County Sheriff's Office investigators were interviewing "a person of interest" in connection with the shooting.

State and county officials also were executing a search warrant at the home of the victim, whose identity was being withheld pending notification of relatives.

Officials said the shooting occurred shortly before 8:40 a.m. outside the gas station on County Road 96, just east of Interstate 35W and not far from the former Twin Cities Army Ammunition Plant site.

Polos said that he had just stopped at the pump when he saw a dark BMW pull up behind him, as if waiting to take his spot. He said he heard yelling in the car and assumed it was directed at him, so he got out to signal that he was going to fill his gas tank.

Instead, he said, the car passed his SUV and pulled up to a parking spot next to the station. As Polos watched, two men got out of the car and the driver shot the other man three times — first alongside the car, then in the back as the victim started to run, and finally in the head from close range as the wounded man pleaded for his life.

The shooter got back into the car, sat there for several seconds — "I don't know what he was doing," Polos said — then backed up and sped forward, running over the victim.

As the shooter drove off, Polos ran to the victim and felt for a pulse, which was faint. The man was taken to Hennepin County Medical Center, where he was pronounced dead, said Sgt. John Eastham of the Ramsey County Sheriff's Office.

Polos noted the getaway car's Minnesota license — 004-EYY — and shouted it over and over, he said, so that people nearby calling 911 could provide it to authorities. He lost sight of the car as it sped west on County Road 96.

"There were a few people there, but most were either in the store or had their backs to the incident. My work helper was in the truck and saw pretty much what I saw," he said.

The Holiday station closed as authorities wrapped the parking lot in yellow police tape and began inspecting the site for clues. Officials interviewed several witnesses and obtained video surveillance footage from the station.

Meanwhile, Polos decided not to proceed to his job as planned.

"I told them I couldn't work and I went to my ex-girlfriend's house and hugged my kids," he said. "That's all I wanted to do."