The police then let rip a fusillade of bullets.
Campbell's body had 25 entrance and graze wounds from the barrage of gunfire, according to the autopsy report. The report also found he had no alcohol or illegal drugs in his system.
He was one of 20 people Philadelphia police shot and killed in the city last year.
This month, the Campbell family sued the city and the officers involved, alleging that the officers used excessive force and engaged in a cover-up.
The Campbells are angry that the police and city have not been forthcoming with details about what happened that Monday nearly a year ago.
The department offered its account of events to the media immediately after the events unfolded, but it has not provided further information to the Campbells, the family says.
A high-ranking police official said that the shooting had been investigated internally and that "we don't see any problem with that job." However, another official said the Internal Affairs investigation remains open.
Tomorrow night - the anniversary of Campbell's death - his family and friends plan to return to the scene of the shooting on Belgrade Street near Allegheny Avenue.
Across the street, at a park coincidentally named Campbell Square, they hope to hold a candlelight vigil in Greg's memory and quietly protest what his parents call the murder of their son.
"I know he wouldn't do something to warrant them shooting him," said Bruce Campbell, 60, Greg's father.
He said police told his family they tried to open the driver's-side door of the car Greg was in but couldn't because of a tree. Police also told his family that Greg was pushing the accelerator, threatening to do more harm to the pinned officer.
Bruce and his wife, Barbara, 59, went to the scene the next day and found no damage on the tree to indicate the car had brushed against it. And they could find no tire marks on the sidewalk to prove that the wheels were spinning.
Bruce's brother-in-law, a retired Vineland detective, was with the Campbells at the scene.
"Get yourself a lawyer," his brother-in-law said after surveying the situation.
The Police Department declined to comment because of the pending litigation, but immediately after the shooting, Internal Affairs Chief Inspector William Colarulo gave the police account of what happened.
A female friend driving an Acura told police she picked up Greg at his home early on the evening of Aug. 21 and the two were going to hang out on South Street. Somehow, for reasons not explained, they wound up in Port Richmond.
The woman, Suzanne Snyder, did not respond to requests from The Inquirer for an interview. Greg's mother said it was her understanding that Snyder had come to take Greg to look at an apartment for rent nearby in Kennett Square.
Snyder told police that Greg was acting oddly and said he had had a fight with his parents and wanted to end it all, Colarulo said. Then he supposedly made a sexual advance toward Snyder, who rebuffed him. She asked him to pull over.
She told police she went into an Arby's on Aramingo Avenue to get a soda, and that Greg took off in her car.
Greg's father acknowledged receiving a call from Snyder that evening. "Mr. Campbell, Greg took my car," he recalled her telling him. "What should I do?"
Bruce Campbell suggested she wait 10 or 15 minutes to see whether he returned. He then called Greg's cell phone and got voice mail. "Return Susie's car. You're acting silly, stupid," his father said in the message.
Barbara Campbell said there was no argument, although there was an awkward exchange between her and Greg that day. She said her son told her he loved her and she replied, "Prove it." She said she had been urging him to spend a month with a Christian youth group to help give him direction in his life and that he had resisted. Greg was working odd jobs at the time but planned to go to school, his family said.
On Aramingo Avenue, Colarulo said, the Acura rear-ended another vehicle. An off-duty federal police officer witnessed the event and was nearly hit when Greg sped away, Colarulo said.
Greg hit two more vehicles and was chased by police, but the pursuit was called off because of the danger to the public, Colarulo said.
When the Acura got stuck in traffic in the 3200 block of Belgrade, officers walked up to the car, ordered Greg out and then tried to pull him out, Colarulo said.
Suddenly the Acura jumped the curb and pinned Officer Frank Luca against the iron fence of the Nativity of the Blessed Virgin Mary Catholic Church.
"We had an individual who literally used his car as a weapon," Colarulo said.
Greg Campbell was shot and killed by Luca and two other officers. Luca was treated and released from Northeastern Hospital, where Campbell was pronounced dead.
Campbell's parents don't dispute that he was pursued by police, possibly for accidents he caused. But they believe the police did not need to shoot him 25 times.
"Our son has been dead for almost a year and the police can't tell us why," his mother said.
Contact staff writer Robert Moran at 215-854-5983 or email@example.com.