Police are working to enhance dark and distant images from crime camera footage that appears to show two people leaving the scene where taxi driver Abdulrahman Ikhtiari was stabbed to death early on Saturday morning.
The footage shows Mr Ikhtiari?s United Taxi Co cab arriving at the area in Worcester Street, near the Barbadoes Street corner, and it is stopped there for a few minutes before the people are seen leaving.
Detective Senior Sergeant Mike Johnson said the images appeared to show two people.
?It is very dark, at a distance, and there are some lighting issues. We are working with it, and we may be able to develop it further to see if we can see more detail,? he told a press conference at the Christchurch Central Police Station this afternoon.
He said the pair might have had blood on their clothing, and they would now be agitated, abnormally interested in the killing and the police investigation, and their behaviour may have changed.
He urged anyone who knew these people to discuss the matter with the police.
Although the original description of the apparent attackers had one of them wearing a bandanna, police were unsure if there were any gang connections.
The police are interested in people going through the area from midnight to 1am on Saturday morning. The crime camera footage shows a dark sedan passing by, heading for Fitzgerald Avenue, and the police want to speak to the occupants.
The post mortem on Mr Ikhtiari indicates the weapon used to stab him in the chest had a blade at least 14cm long and about 2cm wide.
Mr Johnson appealed to occupants of properties in the area to contact the police if they found any items such as clothing, or a knife.
The inquiry is focussing on the identification of the two people seen leaving the area, and the movements of the taxi.
?We want to move this inquiry forward and get some closure for Mr Ikhtiari?s family,? he said.