Stratham Tire manager Jeff Gordon said the video, provided to police, shows an orange glow just three minutes after vehicles headed in that direction. The burning car, off camera, was about 100 yards away in a different parking lot.
Another video, from American Distributors, showed a person running away, an employee told the Bangor Daily News.
The deaths were declared suspicious and the state's deputy chief medical examiner was on the scene Monday afternoon to begin removing and identifying the bodies.
The burning car off Target Industrial Circle was reported by a radio announcer who saw flames on her way to work and dialed 911. The flames popped the car's tires and burst its windows, leaving charred remains.
"It was fully engulfed when I saw it. There was lots of popping and small booms," Kat Walls said. "It was hard to tell it was a car at times because it was so engulfed."
The car was parked near Automatic Distributors, a parts and equipment wholesaler for all-terrain vehicles, snowmobiles, off-road motorcycles and other outdoor activities.
Police were reviewing surveillance video from other businesses, but Bangor police Sgt. Paul Edwards declined to comment on what they contained.
At the scene Monday afternoon were mobile command posts from the Bangor Police Department and the state fire marshal's office. A tent was set up, as well.
Reached at her workplace, Walls said that it never occurred to her that anyone might have been inside the vehicle and that she learned about the bodies when a detective arrived during her morning show at 97.1 the Bear.
"It was horrifying - the idea that I sat there and waited for the fire department while people were burning inside. I'm struggling with it, actually. It feels horrible," she said.