Good Samaritan carjacked by Qld teen

A man who stopped to help four Queensland teenagers who rolled a stolen car has been carjacked by one of the youths.

The man pulled over when he came across the crash scene in the Lockyer Valley west of Brisbane on Tuesday afternoon.

But when he got out of his ute, the teenage driver produced what's now known to be a fake gun, stole the man's keys and fled, leaving his three injured mates behind.

The fugitive driver's passengers, aged 13, 14 and 15, were taken to the Toowoomba Base hospital for treatment for minor injuries.

A police helicopter and dog squad were called in to hunt for the 15-year-old.

He and the ute were found a couple of hours later in Wilsonton, about 20km away from the crash site.

The teenager is facing charges including dangerous driving, armed robbery, unlicensed driving and failing to remain at the scene of a crash. He'll be dealt with under the Youth Justice Act.