A reported single gunshot has sparked a fresh line of inquiry in the long-running manhunt for alleged police killer Desmond Freeman.

Police conducted "firearms testing" near Barrett Lane and Rayner Track in Porepunkah, about 300km northeast of Melbourne in Victoria's northeast, on Wednesday as part of their search.

The testing was triggered by reports of a gunshot in the vicinity about 11.45 am on August 26.

Freeman had allegedly opened fire on police moments earlier, killing Detective Senior Constable Neal Thompson and Senior Constable Vadim de Waart-Hottart and wounding a third officer.

They were among 10 officers serving a warrant at Freeman's Porepunkah home when allegedly confronted about 10.30am.

"The area has since been searched by police, however no trace of Freeman was locate

See Full Page