A  former policeman who has been the subject of two murder investigations over the past 30 years is again under police scrutiny after allegedly being found with an unregistered firearm, unauthorised police identification and ammunition.

The Williamstown home of Denis Tanner, 60, was raided on February 25 and the former police officer was arrested and is expected to be charged with a range of firearm offences.

The raid was launched in response to a February 13 burglary at the Mansfield home of his brother Laurie Tanner, who was also questioned over the death of his wife.

Jennifer Tanner died from two gun shot wounds to the head in 1984 and her death was initially ruled as suicide following a bungled police investigation.

Laurie Tanner reported to police that jewellery belonging to his recently deceased mother was stolen along with wills, titles and other legal documents. The Tanner family are believed to be embroiled in a bitter dispute over their mother's estate.

Mr Tanner told Benalla police he was also missing newspaper clippings that detailed a savage assault on him in 1998 that left him with a 20-centimetre boning knife protruding from his ankle.

Laurie Tanner suddenly withdrew his complaint about the burglary and refused to co-operate with the police investigation following the raid on his brother's Melbourne home.

It is believed police are examining whether Laurie Tanner was pressured to withdraw his original statement.

Detectives from Benalla did not find any of the stolen items from Mansfield, but uncovered a Webley and Scott .22 calibre long-arm air rifle, police-issue ammunition and unauthorised police identification.

Police are investigating how the rifle came into Denis Tanner's possession. 

Denis Tanner could not be reached for comment.

The charges came more than a year after Denis Tanner withdrew his final bid to clear his name over the baffling death of his sister-in-law, who was initially found to have died by shooting herself twice in the head with a .22 bolt-action rifle in 1984.

Laurie Tanner found his wife's body in the lounge room of their Bonnie Doon home. Their 21-month-old son was asleep in the next room, the television was on and no suicide note was found.

First-on-scene police did not take photographs, did not call forensic experts and did not search the house.

A pathologist later found Jennifer Tanner had two bullet wounds through the webbing of both hands.

The first inquest into her death returned an open finding with coroner Hugh Adams saying he was unable to conclude if the wounds were self-inflicted and he cleared Denis and Laurie Tanner of any involvement.

A new investigation was launched in 1995 after the body of transsexual St Kilda prostitute Adele Bailey was found down a mineshaft near the Bonnie Doon property where Jennifer Tanner died.

Denis Tanner was working in St Kilda at the time and was one of the last police officers to speak to Ms Bailey.

Fire destroyed the Bonnie Doon homestead two months after Ms Bailey's body was discovered and it could not be forensically re-examined.

Another coronial inquest was held where Denis Tanner refused to give evidence on the grounds of self-incrimination and coroner Graeme Johnstone found Denis Tanner had killed his sister-in-law.

A year later, in 1999, the Director of Public Prosecutions found there was insufficient evidence to charge him.

That same year Coroner Jacinta Heffey recorded an open finding into Ms Bailey's death and said there was insufficient evidence to establish that Denis Tanner was involved in her death.