Police divers have joined the search for the knife used to stab father-of-two Aaron Hadfield in Wellington.
Mr Hadfield, 27, was stabbed to death on Thursday in an incident thought to have been sparked by road rage, just a few kilometres from his home.
It is believed he was returning home from picking up prescription medicine for one of his young children.
Bystanders tried to revive him after he staggered from his car and collapsed but he died after being taken to Hutt Hospital.
Two men, aged 20 and 22, later handed themselves into police and were both charged with assault, with further charges expected before their next court appearance.