Police have found the knife believed to have been used to kill Christchurch taxi driver Abdulrahman Ikhtiari.
Mr Ikhtiari was found dead next to his cab in Worcester Street, central Christchurch three days ago.
Detective Senior Sergeant Mike Johnson said police found the knife today after executing a search warrant.
A 16-year-old and 19-year-old have been jointly charged with killing
Mr Ikhtiari on December 6.
The pair - both of whom have name suppression - made separate court appearances today.
The 16-year-old wiped away tears during his brief appearance before Judge Jane McMeeken at Christchurch Youth Court.
He did not seek bail and will spend a night in police cells before a bed becomes available in a youth justice facility.
The teenager had a number of supporters in the public gallery and several called out to him as he was led away after his appearance, one person shouting "I love you".
The 19-year-old also made a brief appearance in the district court and stood impassively in the dock.
He also did not seek bail and his name was suppressed until 5pm tomorrow to enable his lawyer Kerry Cook to explore whether there are grounds for extending the name suppression.
As the 19-year-old was led from the court a supporter from the public gallery yelled to him "love you, bro".
Both teenagers are due to reappear in court on December 23.
Last night Detective Senior Sergeant Mike Johnson of Canterbury CIB said police had interviewed the pair after executing search warrants in the Christchurch area which obtained "a number of items of interest to the investigation".
"Despite the arrest of these two males I still appeal to members of the public who have any information about this crime to contact police."
Police yesterday worked to enhance dark and distant images from crime camera footage which appear to show two people leaving the scene where Mr Ikhtiari was stabbed to death in Christchurch 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.
The images appeared to show two people, Mr Johnson said.
"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.
Taxi Federation executive director Tim Reddish said he would speak to the Government about a loan scheme so that taxi drivers could purchase enhanced security gear.
Perpetrators of attacks of drivers were now armed, and knives were quite common, he told Radio New Zealand.
"The whole scene is getting far more dangerous than it was previously."
Taxi companies should insist on their drivers taking proper precautions to keep safe, he said.
There was proven technology, like screens and cameras in cabs, to keep drivers safe. But security gear was quite expensive and most drivers did not have a lot of money.
"I will be talking to the government about perhaps trying to introduce some sort of loan scheme that can enable this equipment to be purchased and paid off over time."