Detectives are reviewing the murders of two schoolgirls following the discovery of fresh evidence 17 years later.

The families of murdered Nicola Fellows and Karen Hadaway have also been given new hope for a retrial over the killings.

The nine-year-old best friends were found sexually assaulted and strangled in Wild Park, near their homes in Brighton, in 1986.

Detectives have confirmed they are re-examining the double killings, which became known as the Babes in the Wood murders.

Russell Bishop was originally charged with the murders but acquitted after the prosecution admitted a series of errors in the presentation of forensic evidence.

The girls' families hope six witness statements, collected by police for the original trial but never presented to the jury, and a receipt from a catalogue company could lead to a retrial.

The evidence focuses on a Pinto sweatshirt forensically linked to the girls.

Bishop's girlfriend at the time, Jenny Johnson, told police it had belonged to Bishop but testified in court she had made the statement under duress.

DNA testing was unavailable at the time.

The family hope the witness statements will link the sweater to Bishop.

One witness, who knew Bishop, said he had seen him wearing the sweater.

There is also a receipt for an identical jumper, said to have been bought for Bishop by his father-in-law.

The 36-year-old roofer, who has always denied any involvement in the killings, is serving a life sentence in York prison after being convicted in 1990 of kidnapping and sexually assaulting a seven-year-old Brighton girl.

He could be released as early as next February, when he can apply for parole.

Under current law, defendants cannot be retried for offences if they have already been acquitted of them.

However, the protection, known as double jeopardy, could be waived under the Government's proposed new Criminal Justice Act, due to be debated today in the House of Lords.

Nicola's uncle, Nigel Heffron, said if double jeopardy was scrapped, he hoped the uncovered evidence would bring about a retrial.

He said: "We want the double-jeopardy law scrapped.

"If we get that, then maybe we will see a retrial. There was evidence that didn't go before the jury."

Detective Inspector Bill Warner of Sussex Police said: "Detectives are now re-examining the murders as part of a wider review of unresolved cases."

"We are awaiting the results of new forensic tests on the sweatshirt."