The genesis of the underworld conflict can be traced to the 1996 arrest of John Higgs, then Australia's number one trafficker of amphetamines. Higgs was a well-connected criminal with a wide network of contacts both in the underworld and among corrupt police, and it took several years in one of the country's most expensive criminal investigations to finally convict him of drug trafficking charges. The case was controversial and included a major cache of drugs linked to Higgs and his syndicate mysteriously vanishing in the storage depots of Melbourne's drug squad, almost certainly thanks to corrupt police involvement. The downfall of Higgs and his closest associates meant younger criminals became keen to enter the drug trade and fill the vacuum left by Higgs' arrest. This included underworld figures such as Jason Moran and Carl Williams who would become key figures in the Melbourne gangland killings.