On 8 December 1987 at approximately 4 pm, a gunman entered the Australia Post building on Queen Street, Melbourne, and opened fire using a sawn-off M1 carbine. Eight employees were killed and a further five were injured.

The massacre ended on the 11th floor, when the gun was wrestled from the offender by an office worker. The gunman then took his own life by breaking a window and jumping to his death.