A light-fingered car thief was soon caught in Calgary, Canada when the car's owner posted a message on an Internet forum.

The thief was easy to identify as he has only eight fingers, with the middle and right digits missing on his left hand.

Shaun Ironside, 27, was selling his distinctive Nissan Skyline GT-R and the thief was posing as a buyer. When the thief did not return from a test drive, Ironside posted a thread on an automotive discussion forum.

More than 46,000 members of the forum then kept their eyes peeled for the thief and he was soon spotted and photographed.

Forum member James Lynch said: "I pulled out my camera, but I wanted to see his hand to be sure, so I made the rock sign that fans of heavy metal music make.

"He returned the gesture. I rolled down my window and said 'Nice stolen car'."

The thief then tried to speed off in the 400bhp Nissan, but the police were soon behind him and he was arrested.

Shaun Ironside said: "I had real confidence in the guys from the forum because I know how many of them are real car fans."

The same forum also helped to catch a hit-and-run driver in 2007.