Christchurch police have launched a homicide investigation after an 18-year-old man assaulted on Saturday morning died in Christchurch Hospital.

Emergency services were called to the Countdown car park on Moorhouse Avenue at 2am after he was found with serious injuries.

The family confirmed to Chris Lynch Media the man died surrounded by family this afternoon.

A man who provided CPR to the victim said at least 30 people were at the scene.

He said the victim was ‘king punched’ but didn’t see the attack take place.

Detective Inspector Joel Syme said “this is a tragic outcome and once again this year we’re investigating the murder of a young person in our community.”

“The victim’s family are tonight coming to terms with their loss and are understandably distraught.”

“We are helping them through this challenging time.”

Police believe they have identified the person responsible for this incident.”

Detective Inspector Syme said “we are confident we know who assaulted this young man and are actively seeking him.”

“We believe this person was solely responsible for the injuries sustained by our victim, and he knows we are wanting to speak with him.”

“At this time, police will not provide any further information about the suspect.”

“There were a group of people present when the assault occurred and we’d like to thank those who have come forward to discuss what they witnessed.

“We know there are others who are yet to talk with us, and we encourage them to do so.”

Anyone with information is asked to contact Police on 105 and quote file number 211204/5631.

Information can also be provided anonymously via Crime Stoppers on 0800 555 111.