A recently excavated skeleton dated to 3677 cal BP provides an extraordinary opportunity to determine the function of its associated backed artefacts. Seventeen stone artefacts were recovered during salvage excavation of an adult male Aboriginal skeleton from a sand dune in Narrabeen, a coastal suburb of Sydney. The skeletal and artefact evidence indicate death by spearing. Three artefacts were refitted, and, of the 14 near complete artefacts, 12 have been clearly backed. One backed artefact was found lodged between the L2 and L3 vertebrae with unhealed wounds, indicating spear penetration near the left hip. Other backed artefacts were found adjacent to or lodged in vertebrae suggesting two spears had penetrated from the back. Breakage and use-wear on most artefacts indicate use as barbs or 'lacerators'. In this study, we describe the use-wear and suggest possible hafting arrangements of these backed microliths, which probably functioned as piercing, cutting and lacerating elements of spears and knives.