Today Detective Senior Sergeant Greg Baird said it was thought the item of interest may have been disposed of in the suburb of Richmond.
"Specifically, we're hoping to locate a knife, which is thought to be 20-30cm long.
"Finding this item would greatly assist our investigation, so if you live on the block bound by Lorn St, Yarrow St, Tay St and Lithgow St, please do take a look.
"Anyone using the sports fields and facilities in this area is also asked to keep an eye out."
Anyone who finds a knife matching this description should not touch it and instead call Police immediately on 105 and quote file number 220429/9172.
On Tuesday, a 26-year-old Invercargill man appeared in the Invercargill District Court by audio-visual link after being charged with the alleged murder of Chad Parekura and attempted murder of a second man, on April 23.
Police were alerted to the double-stabbing, near the courthouse in Don St, just before 12.45am on Saturday and found Mr Parekura unconscious. He died at the scene.
The other victim was transported to Southland Hospital with critical injuries.
The defendant was arrested in Invercargill on Monday.
Police confirmed this afternoon the second victim has now been discharged from hospital and continues to recover at home.
Enquiries to establish the full events that occurred on the evening of Mr Parekura's death are ongoing.
