Sydney - Australian police are investigating the slaying of Sydney man Chen Liu, who was killed by 27 nails fired into his head with a high-powered nail gun normally used on construction sites.

"Similar types of nail guns can fire nails up to 85 millimetres long," homicide squad detective Inspector Mark Newham said Friday.

Liu's decomposed body was found by schoolboys in marshland in October in Sydney, but police have only just released an X-ray showing the nails embedded in the 27-year-old's head. (dpa)