In April 1926, at Mossman, a sugar-cane growing area, north of Cairns, Far North Queensland: Phillip McClean died after receiving an injury to the throat. He had tried to protect his dog, which was being attacked. Below is a typical report from the internet.
The one documented human death was caused by a cassowary on 6 April 1926. 16-year-old Phillip McClean and his brother, aged 13, came across a cassowary on their property and decided to try to kill it by striking it with clubs. The bird kicked the younger boy, who fell and ran away as his older brother struck the bird. The older McClean then tripped and fell to the ground. While he was on the ground the cassowary kicked him in the neck, opening a 1.25 cm (0.49 in) wound which may have severed his jugular vein. The boy died of his injuries shortly afterwards.
I managed to find the original Cairns Post newspaper story which is somewhat different. Phillip (17) and brother Granville McLean (14) were out looking for their horses, when their dog bailed up a large cassowary. Granville rushed in to help the dog who was getting beaten up, and got kicked in the leg. Brother Phillip then attacked the cassowary with the horse bridle he was carrying, and was struck in the neck. Phillip ran towards home, but only made about 200 yards before bleeding out.
My next step is to see if I can locate the coroner's report.
I have written another longer article How dangerous is the cassowary? which includes video footage of a recent magic encounter with a family group of cassowaries.