Police in Wellington are trying to work out how a 20-year-old man ended up with serious injuries on Friday night.
The man left a party in the central suburb of Mt Victoria shortly before midnight and returned about 10 minutes later with head and face fractures, a broken arm and
several grazes.
He is in a stable condition in Wellington Hospital.
Detective Sergeant Corey Watts said while information suggested he had been assaulted, other causes had not been ruled out.
"Police are working to establish how this young man received these serious injuries, and we are looking at a number of possibilities," he said.