This Australian contract killer was active from 1980 to 1985, during the Sydney gang wars. While he worked for anyone who paid, Flannery primarily sided with crime boss Neddy Smith. It's uncertain how many people Flannery killed, though it's at least in the double digits.
What is certain is that around 1984, he became increasingly paranoid and began going on random assault rifle killing sprees, which police came to blame on his employer. Flannery is considered to have extended the Sydney violence substantially. Even when his employer told him to stop the killings, Flannery refused. When the police showed up at a meeting with the crime bosses, attempting to negotiate a peace, Flannery told one high-ranking officer "You're not a protected species, you know – you're not a f***ing koala!"
Mister Rent-a-Kill went missing in 1985, quite possibly the victim of his former employer, who had lost control of his contract killer. However, with the number of enemies this hired gun made in Sydney, it was probably only a matter of time before the sharks of the Great Barrier Reef got a free meal.