Since November, and as recently as three months ago, police investigators had been in contact with him and other former employees of Griffith’s The Area News for information about one of their colleagues, whose name has been withheld. 

The journalist, who passed away about a year ago, covered the trial of those accused of being behind one of Australia’s biggest drug busts at Coleambally in November 1975.

It’s believed something they’d written down at the time may have since surfaced. 

As the editor of the paper at the time Mr Mackay disappeared, Mr Jones had spoken to him many times, including in the week before his bloodied car was found outside the Griffith Hotel. 

However, where the latest search “off the beaten track” on a property near Hay will lead – or what will be unearthed – is still anyone’s guess.

Speaking exclusively to The Daily Advertiser, Mr Jones said the latest search was the biggest since divers searched the Murray River near Tocumwal about 30 years ago and joined a series of others which have all proved fruitless. 

“Why they’ve been asking about (the journalist) ... I suspect (they) must have written something down and a member of his family must have found it.

“I’ve got to think it might be a family member looking for the reward. 

“To put in the effort they have, you’d think it’d have to be a pretty strong lead.” 

During the trial of the Coleambally accused, the counsel for the defence obtained diaries and, more specifically, notebooks of the investigating police.

In the notebook were the names of various informants and, when it exchanged hands, The Area News journalist said they’d effectively signed Mr Mackay’s death sentence.

“They’ll never have a murder weapon, but if they have remains ... if they can DNA match with Don’s blood group and match the hair in his brush and from beside his car, then they have the opportunity to charge somebody with murder.”

Mr Jones, who has followed the case “quite keenly”, played down the new information provided to police, which speculates Mr Mackay was bundled into the boot of a car and driven to the Hay property by two hitmen before the killers continued on to Melbourne. 

“It’s not your main road from Griffith to Melbourne,” he said.

“This search out there is really off the beaten track ... it’s really out of the blue,” Mr Jones said.

Mr Jones said it was documented by the Nagle Commission of Enquiry that mafia informer Gianfranco Tizzoni owned properties in the Riverina.

“He may well have owned a property near Hay ... a family member – that is a long way removed from the hit – may well know and they’re as entitled as anyone to the reward.”