On 15 July 1977, Mackay disappeared from the Griffith Hotel car park after having drinks with friends. His body has never been found. At the scene of his disappearance, his locked van had bloodstains on the door, wheel rim, mudguard and tyre and his car keys and three spent .22 casings were found. Trimbole is believed to have arranged the contract style killing of Mackay. Woodward Royal Commission The disappearance of Mackay prompted a royal commission into the Griffith drug trade, known as the Woodward Royal Commission after its sole commissioner, the Honorable Philip Morgan Woodward. After several months, the Commission reduced the suspect list to six people including: Robert Trimbole James Frederick Bazley George Joseph Gianfranco Tizzone and two known associates of Trimbole. Justice Woodward says in the official transcript, "I have named Trimbole as being associated with the production of marijuana in Griffith as well as being the director of an operation in Euston. He is, if not the 'top man' in relation to the production of marijuana in the Griffith area, then one of them and closely associated with Antonio Sergi in the same enterprise." Woodward found regarding the disappearance of Mackay that "the disposal of Mackay was the result of an organised plan. He was disposed of by the organisation which I find existed in Griffith. I am satisfied that the appointment to meet Mackay at Jerilderie was part of a plan to ambush and dispose of him." A year later the New South Wales Supreme Court officially declared Donald Mackay as "presumed deceased". No further action was taken. Trimbole and his associates were free to return to business as usual. Coroner's inquest Seven years after the Woodward Royal Commission, political and media pressure called for an inquest into Mackay's death, which was eventually held before Coroner Bruce Brown. The inquest also heard evidence showing that lights in the car park had been broken before the meeting time set with Mackay, indicating a premeditated act to ambush him, and that Mackay feared for his life after learning that the crop leading to the convictions of the four men had an estimated street value of more than A$25 million. Evidence was also submitted regarding a man by the name of Patrick Joseph Keenan who made a statement to police that he had walked into a shed in the Griffth area and found Antonio Sergi inside with several