Detective Senior Sergeant Scott Cooper said police were looking for a knife, thought to have a blade seven to to 10cm long, possibly with a wooden handle.
"We are also speaking to family, friends and associates of Aaron Hadfield and those who were in the vicinity of George and Logie Streets on Thursday night, to piece together the events which led to his death. We are still very keen to hear from anyone who may be able to provide any information to police."
Police also wanted to speak anyone who saw the two accused in the area on Thursday night.
One was a Pakeha, wearing a black baseball cap, shorts and a green "Celtics" hoodie.
The other was Maori, wearing a grey-patterned hoodie, black t-shirt and possibly brown shorts. He had dark hair with a strip of blonde down the middle.
They were both granted interim name suppression when they made their first appearance in Lower Hutt District yesterday afternoon.
Both had support from family members and some were heard yelling out "I love you, son" and "you'll be all good, baby" from the public gallery.
A group was crying quietly through the entire appearance.
The 22-year-old man's lawyer, Geoff Fulton, said he would not apply for bail for the man until what was likely to happen with the case was more clearly determined.
Judge Peter Butler remanded the 22-year-old in custody for his next appearance on February 9.
Lawyer for the 20-year-old, Geoff Fulton, did make an application for bail.
However, Judge Butler said today was not the time to make an application for bail and remanded him in custody until his next appearance on February 14.
Mr Hadfield had two children; Kayleb, aged two, and Aaliyah, five.