Police are investigating witness reports of a single gunshot heard near Dezi Freeman’s property shortly after he allegedly killed two police officers in August.

On Wednesday, police conducted “firearms testing” around Barrett Lane and Rayner Track in Porepunkah, after reports of a gunshot in the area about 11:45am on August 26.

Mr Freeman was last seen fleeing his Rayner Track property on foot following his alleged attack on police executing a warrant after 10:30am that morning.

Rayner Track sign

Police have undertaken firearms testing around Rayner Track, near where Dezi Freeman was last seen. (ABC News: Patrick Rocca)

Detective Leading Senior Constable Neal Thompson and Senior Constable Vadim de Waart-Hottart were killed, while a third police officer was seriously injured.

Mr Freeman has not been seen since and a $1 million reward for information related to his whereabouts remains in place.

Police say they have since searched the area and have found no trace of Mr Freeman, while investigators say they are hopeful the firearms testing will help with the ongoing search.

Authorities are also keen to speak to anyone who had heard the gunshot, including those who believed they could be the person responsible.

Last month, police announced a new taskforce would take the lead in the ongoing search for Mr Freeman in Victoria’s north-east.

Anyone who has seen Mr Freeman should phone triple-0 immediately and not approach him, and anyone with information about his current whereabouts has been urged to contact Crime Stoppers online or on 1800 333 000.