A man has been arrested and charged after a violent attack on a "good Samaritan" in Queenstown in March.
But the alleged victim will also be charged after police established the attack was not random and he knew the accused.
In March police appealed for information about the attack, saying a Good Samaritan suffered a fractured jaw after an assault and robbery at the Eastburn Rd layby on the Queenstown side of the Crown Range.
They said a man signalled for help using a cellphone torch, claiming something was wrong with his vehicle.
As the victim turned away, he claimed the man punched him several times, grabbed the victim's backpack and drove off.
The victim was able to drive to a family member's house, where police were called.
He was then taken to hospital and is awaiting surgery on his fractured jaw.
At the time police described the incident as "a cowardly attack on a well-meaning person trying to help someone he thought was in need".
Today Detective Senior Sergeant Malcolm Inglis confirmed a 20-year-old Cromwell man had been arrested charged with the robbery.
He is due to appear in Queenstown District Court on Monday 10 May.
Inglis said the man originally portrayed as an innocent good Samaritan would also face the courts.
"Police inquiries have now established the pair were known to one another and the meeting, which actually occurred in the car park at Coronet Peak, was pre-arranged," he said.
"Police are satisfied that this was not a random attack and that other criminal activity was involved. As such, we expect to charge the 21-year-old with making a false statement to police."
Inglis would not be drawn further as the matter was before the courts.