Dennis Bruce Allen (7 November 1951 – 13 April 1987) was a notorious Australian drug dealer and alleged serial killer based in Melbourne.

However, Allen died of heart disease in 1987 while in prison custody, awaiting trial for murder.

[3] Dennis Allen, known as Mr. Death or Mr. D,[4] was suspected of involvement in up to 13[a] underworld murders, including the gruesome chainsaw dismemberment of Hells Angels biker Anton Kenny in 1985.

[4][5] Interestingly, New South Wales Police Detective-Sergeant Roger Rogerson was convicted of supplying heroin in a deal with Allen, but was later acquitted on appeal.

[7] Allen managed to evade capture and prosecution by possessing incriminating information against corrupt Victorian police officers.