A year after the brutal murder of a teenage prostitute, a leading police officer made a heartfelt appeal for help in catching her killer.

The last known sighting of Becky Hall was on Good Friday when she left her Bradford home, thought to be headed for the city's red light district.

Thirteen days later, her savagely beaten body was found in an alleyway behind a car park at Thornton Street, just yards from where she and other prostitutes worked.

Police believe the mum-of-one, from Lydgate House, off Elizabeth Street, Little Horton, was killed shortly after her disappearance but her body laid undiscovered for 13 days. Rebecca's son Jordan was just four months old at the time of her murder.

Today Chief Supt Max McLean, who is leading the murder investigation, said: "Although there are still scientific tests on-going to determine exactly when Becky died I believe she was probably murdered last Good Friday."

He said: "I am appealing to people to think back to Good Friday last year. Did you see Becky? Did you see anything suspicious in that area of Bradford that didn't look quite right?"

He added: "Perhaps a year ago your circumstances were different and for some reason you felt you couldn't come forward to the police."

He said it could take one piece of information - which might seem insignificant to the holder - to finally trace the murderer.

"It is a regret of mine that in my four years as the senior detective in Bradford this is the only murder I have so far failed to detect, but this case is very much still open and the hunt for Becky's murderer goes on," said Chief Supt McLean.

"We have had very little information from the public. I realise this is probably due to the trade Becky worked in, but I would like to remind people that Becky was a 19-year-old mother of a four-month-old baby boy. Her killer must be caught."

Rebecca was 5ft 5ins tall, slim, with dyed red hair in a bobbed style. When she was last seen she was wearing black leggings and a purple sheer top.

Chief Supt McLean became divisional commander of Calderdale Police last month but remains involved in the hunt for Becky's murderer.

Anyone with information is asked to contact Bradford South police on (01274) 376485.