Police have descended on a Porepunkah street overnight in the hunt for alleged gunman Dezi Freeman, as the search for the accused cop killer enters day four.

At 8.30pm yesterday, at least 12 police vehicles arrived in the street in the Victorian high country town, about 300km from Melbourne.

At the same time an emergency alert was issued to everybody in the Porepunkah area advising residents that police were searching for an armed offender and they should limit travel.

Officers dismounted and surrounded a property as a loudspeaker advised people inside to come out with nothing in their hands.

About 10 people walked from the home before they were searched. Officers led away a woman and a baby. Nobody in the house is accused of any wrongdoing.

Police would not comment on the operation and only said the investigation was ongoing.

Also overnight, an emotional vigil was held in the town of Wangaratta for one of the officers shot dead in the attack.

The town is where Detective Leading Senior Constable Neal Thompson, 59, used to work. He was only two weeks away from retirement when he died.

Freeman is accused of shooting dead Thompson and Constable Vadim De Waart on Tuesday morning at a home in Porepunkah.

A third officer was allegedly shot and wounded in the leg and is recovering in hospital.

Freeman is a self-described “sovereign citizen” who is known to police.

According to the Australian Federal Police, a sovereign citizen – also known as a SovCit – seeks to “disassociate from society and refuses to engage with societal requirements like paying tax”.

Police said he had several firearms on him, with senior officers confirming police had not recovered any weapons used in the attack.

Hundreds of officers and specialist police have swarmed the small country town as Victoria Police commit every resource available to track down and apprehend Freeman.

Police are still working on the theory that the accused gunman remains in the Porepunkah area.

Deputy Commissioner of Regional Operations Russell Barrett said yesterday the search area had been expanded but Freeman was believed to be close by.

He also said the manhunt had been taking longer than expected.

The rough terrain has been making the search difficult.