Christchurch police are appealing for a group of four young people to come forward over an attack on a German backpacker at the central city bus exchange early on Saturday morning.
Two women and two men were captured on CCTV cameras at the same time as the attack happened.
Police say they may not have been involved, but could still have vital information about the assault.
The backpacker found himself alone in the city after being denied a bed for the night at Christchurch Hospital, where he had just undergone treatment for an eye infection.
