A post-mortem examination revealed that Mr Liu was shot 34 times
Australian police have released an X-ray image showing the skull of a murdered Chinese immigrant shot repeatedly with a nail gun.
Police are appealing for help to solve the murder of Chen Liu, 27, whose body was found by two children last year in marshland in south Sydney.
Detectives said the weapon was a gas nail gun used in construction, firing nails up to 85mm (3.3in) long.
Mr Chen arrived in Melbourne in 2000 on a student visa, and moved to Sydney.
A post-mortem examination revealed that Mr Liu was shot 34 times in the head and neck with a high-powered nail gun, police said.
The weapon has not yet been recovered. Police have appealed for information from anyone who may have been in the area at the time of Mr Chen's death.
"In 36 years, I've never seen a murder of this nature," Homicide Squad Superintendent Geoff Beresford told reporters.
"It's a particularly brutal and vicious murder and hence the reason we are seeking information from the public," he said.
Mr Chen's badly decomposed body was found on 1 November 2008, wrapped in plastic, wire and an electrical cord.
"We believe the perpetrators had every intention of the body not being discovered," Supt Beresford said.
"Certainly there were efforts made to perhaps weigh it down if you like, and it was the force of nature, the tides, whereby the body has been discovered on the river bank."