Mr Beer, 54, was shot once in the chest with a high-powered rifle as he used a tractor at his Tallandoon property on Lockharts Gap Road.

His body was discovered by a passing friend on February 7, 1994, and it’s believed he was shot the previous afternoon or night.

Friends, family members and police investigators hope a $1 million reward, which will come into effect next week, will help solve the crime.

“I’ll never forget it,” Mrs Mahoney said, voice quivering, as she recalled hearing her brother had died.

“I was playing golf and looked at my husband.

“I just knew something was wrong by his face.

“He said ‘David’s dead, someone has shot him’.

“It was the worst day of my life and I’ll never forget it.”

One of the hardest things for Mrs Mahoney is the thought her brother will be forgotten and the killer never face justice.

“It’s very frustrating,” she said. 

“How can you hate someone so much as to take their life?

“I don’t understand that.

“I’ve been harassing (the Homicide Squad) since it happened.

“I just don’t want him to be a box in the cupboard gathering cobwebs.

“I can’t accept that.

“He can’t be forgotten.”

A four-day coronial inquest in 1999 heard Mr Beer had been in a long-running battle with his neighbours, David and Brenda Supheert, in the years leading up to his death.

It started as an argument over water access and turned into violence.

The coroner heard Mr Beer was seriously assaulted with a wheel brace almost two years before his death.

He launched civil action for his injuries against Mr Supheert only three days before he was shot.

Coroner Kevin Mason could not find who shot the 54-year-old, but found his neighbours had motive to “do some harm” to him. 

“An appraisal of all of the evidence indicates in so far as Mr Supheert and for that (matter) Mrs Supheert is concerned, that they most certainly had a motive to do some harm to the deceased,” he said. 

“They were in the vicinity at the time.” 

The case has been re-opened several times, but no-one has ever been charged. 

Homicide detectives have not eliminated Mr Supheert as a suspect during their investigations. The coroner heard Brenda Supheert had made a statement to police about her husband’s actions on the night that Mr Beer was killed. 

“(He) tossed a gun down on the back step and said words to the effect that it’s stuffed now, it doesn’t matter anyway, it’s all over,” she said in the statement. 

The $1 million reward for new information leading to a conviction will come into play on Wednesday, coinciding with the airing of Channel 7 show Million Dollar Cold Case.

The reward is currently $100,000, having earlier increased from $50,000. 

The show will document the 23-year-old murder, with original investigator Detective Inspector Phil Shepherd hoping the cash will get people talking.

“We would really hope that the million dollar reward would be something that would help people think long and hard about what is really the truth of what happened on that night,” he said.

While the focus has been on Mr Supheert, who lived on the other side of Lockharts Gap Road, police say that hasn’t been to the detriment of other angles or suspects.

They are open to receiving any information.

Mr Beer’s son, Wayne, still thinks about his father all the time and misses his love.

When heard his father had died, he instantly knew he had been murdered.

“We can’t bring dad back, we can’t stop hurting every day,” he said.

“But we can at least have justice, to know the person who killed him is no longer running around, scot-free.

“It caused a final split up from my mother and the rest of the family … the pain sticks with you every day.”

In the show, Detective Inspector Shepherd says Mr Supheert had not co-operated with police.

“At no stage have we had any explanation from David Supheert about what he was doing leading up to and at the time of David Beer’s murder,” he said. 

Mr Beer was born in Tallangatta and went to primary school at Tallandoon before attending high school at Wangaratta. He worked for Elders Real Estate in Albury at the time of his death.

Mrs Mahoney said she still thinks of her brother “with a lot of love” every day.

“The hardest part is probably accepting what happened, that someone killed him,” Mrs Mahoney said.

“Had he been killed in a car accident or by sickness, you could understand that and accept it.

“To think someone deliberately took his life, that’s very hard. With the TV show, I’m hoping someone will come forward. Someone can clear their conscience.

“They can start a new life with a million dollars and we can have peace and a bit of closure.”

Detective Sgt Paul Bubb said police were seeking evidence of an admission. 

Anyone with information can call 1800 333 000. 

Million Dollar Cold Case will air on Prime7 on Wednesday at 9pm.