Detectives have demanded DNA samples from more than 300 South Croydon men in a bid to hunt down the man who killed teenage model Sally Anne Bowman.

Police said 327 men have been visited by officers after failing to voluntarily submit a DNA sample at the temporary screening centre opened at Brighton Road Baptist Church.

The screening office which opened for two weeks on February 27 was one of the largest DNA operations undertaken by the Metropolitan Police Service.

Around 4,000 local men were sent letters asking them to voluntarily provide a sample, but fewer than 500 attended the screening centre of their own volition. Those who did not are now being sought by police and face arrest if they fail to comply.

Last weekend an additional 80 murder detectives from across London took part in an operation to obtain DNA samples from men.

The news comes after Sally Anne's father, Paul Bowman, revealed on the Trevor McDonald Tonight programme on Monday night he fears his daughter's killer may never be caught.

Six months after his blonde daughter was stabbed to death and sexually assaulted Mr Bowman told of his anguish at how the killer "blatantly walked away".

However, Detective Chief Inspector Stuart Cundy, the man leading the murder hunt, insists he is still confident that Sally Anne's murderer will be caught.

He said: "Sally Anne Bowman's killer will be caught. He will be brought to justice. We need the public's assistance to catch him as soon as possible. It is vital the public assist us to catch this man.

"We need to make South Croydon a safer place by arresting him therefore urge anyone who thinks they even slightly recognise the e-fit to please call the incident room."

Since the release of the new e-fit of Sally Anne's killer police have received more than 100 calls to the incident room.

Detectives have taken phone calls from members of the public who have provided information and names of possible suspects following the release of the computer generated e-fit last Wednesday.

Anyone with information should call the incident room on 020 8721 4005 or Crimestoppers anonymously on 0800 555 111.