Police talk to pub regulars as £50,000 reward offered to find Joanna's killer

Yesterday officers were also talking to customers in the pub visited by the landscape architect on the night she disappeared, three weeks ago.

The 25-year-old had spent about two hours with work colleagues in the Ram pub in Bristol city centre on December 17.

To mark three weeks since she disappeared, plain- clothed officers were speaking to regulars in the Ram, which is close to where she worked at BDP with her boyfriend Greg Reardon, 27.

Avon and Somerset Police have been searching around 40 drains in the streets surrounding Miss Yeates' home.

Miss Yeates left the pub in Park Street at around 8pm to make the 30 minute walk home to the flat in Canynge Road, Clifton, that she shared with Mr Reardon.

She visited three shops on the way home and was filmed on CCTV buying a pizza in Tesco Express, Clifton.

The receipt was discovered in her flat but no evidence of the pizza or the packaging has ever been found.

Miss Yeates's snow-covered body was found in a country lane in Failand, north Somerset, on Christmas morning eight days after she disappeared.

She was discovered just three miles from her home and had been strangled.

Avon and Somerset Police have said there was no evidence Miss Yeates was sexually assaulted but they have not ruled out a sexual motive.

The Sun newspaper has offered a 50,000 reward for finding the killer, in addition to the 10,000 already offered by Crimestoppers.

So far the police have made one arrest – Miss Yeates's landlord Christopher Jefferies. The 65-year-old was held for three days on suspicion of murder before being released on bail.

Now Mr Jefferies, a retired former teacher at the exclusive Clifton College, is reportedly considering suing police for wrongful arrest. One of his friends said: "He is preparing a case. This has completely shattered his life."

Officers are investigating whether Miss Yeates could have been strangled with her own ski sock, which her killer might then have kept as a trophy.

Her body was found missing one of her grey, knee-length socks, and detectives believe the garment may hold the key to solving her murder.