Describing herself as a friend of the Mackay family, she handed in a photocopy of a hand-written note in to the Griffith police as well as to The Area News, after an article about the 42^nd anniversary of his murder in the paper on Wednesday "hit too close to home".

While not knowing if the anonymous message refers to the final resting place of the assassinated anti-drug campaigner, the "strange and unusual" letter had "never sat right" with her.

Wishing to remain anonymous until if or when anything was found as a result, she said she had kept a copy even during moving house and after the death of her husband.

She said her husband had worked for Italian growers in the area who "respected and trusted" him.

At the time the couple received the letter, she estimates about five years ago, she handed the note into police and to this day has no idea what became of it.

Griffith police Chief Inspector John Wadsworth said while they were told the note had been handed in previously, they would make sure every piece of information they received was examined.

"What I will say the person who gave us the document advised us it was given to police at the time, but if there is any chance, if there is any possibility, we will take it very seriously," Chief Inspector Wadsworth said.

He commended her actions, saying they were a "great sign" people were taking their call for information seriously.

"We have received the information, as much as we have received a lot of it," he said.

"It's good to see the community has taken heed of our message - that it's never over till it's over."

With the letter's delivery around early 2014, it came after an extensive police search conducted on a property on Maude Road in Hay during 2013.

The search came after police re-investigating the murder were told two hit men dumped the body in a well at the property on their way back to Melbourne.

The working theory at the time suggested Mackay was shot in the car park of the Griffith Hotel, and driven to a Hay in the boot of a car, to a property 150 kilometres away.

The hitman suspected of killing of Mr Mackay, James Frederick Bazley, died in November 2018.

He is suspected of being paid $10,000 in a high profile Mafia plot to kill Mr Mackay in 1977, before he disposed of the businessman's body.

Bazley walked free from a prison in 2001, and aged in his early 90s, spent his last years in a Melbourne nursing home after suffering ailing health.

It is believed the remaining secrets of what has been called one of Australia's most enduring murder mysteries was buried with him.

And yet while this potentially helpful letter may aid police in their investigations, it does not mean more information would be appreciated from the community.

Chief Inspector Wadsworth remained hopeful more of the community would come forward with any information, old or new.

Those wishing to come forward can do so by visiting of calling Griffith Police Station on 6969 4299.

Alternatively contact Crime Stoppers on 1800 333 000 or visit nsw.crimestoppers.com.au.

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