A bear climbed into an empty car in the US state of Colorado, sounded the horn and sent the vehicle rolling down hill with the terrified animal still inside.

The car's owner, 17-year-old Ben Story, took a snap of the panic-stricken bear as it demolished the inside of his vehicle in its bid to escape.

Police in Larkspur, near Denver, eventually freed the animal by opening the door from a distance using a rope.

It is believed the bear was attracted by a sandwich left on the back seat.

Mr Story and his family were asleep when the bear opened the unlocked door of his 2008 Toyota Corolla in the early hours of the morning and climbed inside.

Mr Story's father, Ralph, said the bear must have hit the car's automatic transmission into neutral sending it rolling backwards 125ft (38m), off the driveway, down an embankment and into a thicket of trees.

"The four-way flashers were on. It's like he knew what was going on, and kept hitting the horn," he told Denver's 7News.

Once the car door closed behind the bear, it was trapped inside.

Ben Story said his car was wrecked.

"It was a pretty good size, actually it was pretty big. If you look at the inside of the car, there's nothing left at all. You could see it moving around, it like took up the entire inside of the car."

The bear was last seen running into the woods.

Colorado wildlife expert Tyler Baskfield said bears often entered cars and houses in search of food.

"It happens all the time," he said. "They're very smart."