The Mangakakahi Stream in Rotorua is currently the scene of a police search for evidence relating to the murder of security guard Howard Percy in 1976.
Bay of Plenty Police announced earlier this week that they were reinvestigating Mr Percy's murder to make the most of advances in science and technology and to follow up on new information that had come forward in recent times.
Today the Police National Dive Squad, Police search and rescue trained personnel and volunteers from LandSAR began a search of a kilometre stretch of Mangakakhi Stream and its banks between Sunset Road and Pururu Street.
Detective Inspector Tim Anderson said: "We are searching for evidence relating to Mr Percy's death; specifically a firearm believed to be a .22 sawn off rifle. We have received information from a reliable source that the weapon thrown into this stream after the robbery.
"I am not prepared to say when we received this information or from who but I can say that reliable information we received prompted us to escalate the investigation and we have also received information since releasing details of the 0800 4 PERCY phone line on Wednesday."
Over the last 36-years the banks of the stream would have changed so the search is a slow and painstaking task. It is not clear at this stage how long the search will continue.
"I am keen to hear from anyone who has found a firearm in the area of the stream since 1976, or has any other information that might assist the investigation. Even if it seems irrelevant it might still be important," said DI Anderson.
Anyone with information is asked to call 0800 4 PERCY (0800 473729) or email Operation.Percy@police.govt.nz. Alternatively information can be provided anonymously via Crimestoppers on 0800 555111.
Media enquiries should be referred to Communications Manager Kim Perks on 027 234 8256.