Police investigating the New Year's day killing of an expat Kiwi at Waihi Beach are appealing for a mystery person who handed in a knife to come forward.
Robert Murray Wilkinson, 64, died in Waikato Hospital on Thursday from stab wounds he suffered when he was attacked outside a caravan parked in the driveway about 1am on Tuesday.
On the night Wilkinson died, a member of the public handed in a knife to a security guard who was guarding the crime scene.
Police said the person did the right thing, but unfortunately no details were taken and they need to know where the knife was found.
Detective Inspector Page said it was incredibly important to the investigation.
"It is not known if this knife has anything to do with the incident, but for the investigation it is very important for us to know where the knife was found, when, and by who.
"These are the sorts of details that help us to determine what is and is not relevant in cases such as this."
The case was upgraded to a homicide investigation and yesterday afternoon members of Wilkinson's family spoke of their grief.
His wife Luise, son Dan and daughter Cory Rance, gathered at Hamilton police station to deliver a statement.
They said they were ''desperate'' to understand why he was killed.
''It's impossible to express the complete devastation the family are now going through,'' Dan Wilkinson said.
Page said teams of police were still conducting wider area searches today.
The investigation is now in its fifth day, which police said had been "buoyed" by the high level of public support.