04:13 EDT, 14 December 2020 Zack Mavin (pictured), 24, is accused of murdering Robert 'Bobby' Palmer, 54 A man allegedly armed with a knife and explosive device tried robbing a service station minutes before stabbing a much loved footy legend to death, a court has heard. Zack Mavin, 24, is accused of murdering Robert 'Bobby' Palmer, 54, outside Metro service station on Sandgate Road, Shortland in Newcastle, NSW on Saturday night. He appeared in Newcastle Local Court on Monday charged with murder and attempted robbery armed with an offensive weapon. The court heard that moments before the alleged stabbing, Mavin had attempted to rob a service station with an improvised explosive device, ABC reported.