A biker's nightmare - a hijacker calmly pulls up alongside, he's hijacked at gunpoint and the gunman tries ride off on his bike. Fortunately, a nearby cop defuses the situation - he opens fire. All of this, captured by a helmet-cam!A biker's nightmare - what would you do if a hijacker tried to take your motorcycle at gunpoint? This one in Brazil fell victim to two biker thieves. What's more his helmet-cam captured the shocking ordeal and its eventual deadly outcome.Video: Cop guns down motorcycle hijackerThe video, posted on LiveLeak, shows a pair of thugs on another motorcycle pull up next to a biker at a junction. The hijacker, riding pillion, pulls out a very large handgun and forces the rider off his bike, which falls to the road. Unbeknown to the thief, a police officer who was in an unmarked vehicle aproaches the hijacker and fires two shots at the thief, who is knocked off the bike. His accomplice flees. It all happens rather quickly so you'll probably have to watch the video more than once to see what went happened. No doubt this shocking footage will encourage bikers to invest in a helmet cam.Do you think the cop was justified in shooting the rider? Email us and we'll publish your thoughts on Wheels24.