Police are investigating whether murder victim Joanna Yeates could have been strangled with her own ski sock, which her killer might then have kept as a trophy.
The landscape architect's snow-covered body was found on Christmas morning missing one of her grey, knee-length socks, and detectives believe the garment may hold the key to solving her murder.
The 25-year-old, who was last seen alive nearly three weeks ago, was not wearing her coat or boots either but those items were recovered from her flat in Clifton, Bristol.
Det Chief Inspector Phil Jones, who is leading the murder hunt, held up a similar size-five sock on Wednesday to the one Miss Yeates was wearing.
He said: "The jacket and the boots have been found at her home address. That would indicate that Jo had returned home.
"However, at this present time the sock has not been found. It hasn't been found (where her body was) and it hasn't been found at her home address."
The detective said he was "keeping an open mind" about whether the killer or killers could be keeping the sock as some sort of trophy or whether Miss Yeates was strangled with it.
Following the appeal for the missing garment, a man approached police outside Miss Yeates's flat and handed over a grey sock.
The sock was put into an evidence bag but later police said at this stage it was not the one they were looking for.
Mr Jones also confirmed that the killer or killers may have tried to put Miss Yeates's body over a wall into the quarry on Longwood Lane, Failand, North Somerset, but instead left her on the grass verge.
As the three week anniversary of her disappearance neared, Mr Jones would not confirm directly that police were using a criminal profiler but said his team were receiving assistance from various expert sources.