Police have revealed they have the full DNA profile of a man who was with murdered woman Mellory Manning about the time she died.
The 27-year-old, who was working as a prostitute, was strangled, beaten and stabbed on 18 December 2008. Her body was found dumped in the Avon River the following day.
At a news conference on Thursday afternoon, police appealed for any clients or sexual partners of Ms Manning to come forward.
Detective Inspector Greg Williams says the DNA profile was extracted from a semen sample recovered from her body. Police have not publicly acknowledged its existence until now.
Mr Williams says during the 1000 days of the investigation, hundreds of people known to police have had their DNA checked against the sample.
Mr Williams says no match was found, even when compared with Ms Manning's then partner, or the two clients she was with on the night she died.
He says it appears Ms Manning was attacked at a Mongrel Mob gang house on 18 December 2008, before being dumped in the river.
Mr Williams says it is likely she was subjected to a sexual attack and that more than one person was involved in her death.