Police are pursuing new lines of inquiry into the murder of two nine-year-old girls in a Brighton park.

Detectives said they could not give details but the investigation into the 1986 Babes in the Wood killings was progressing.

They have given the operation a codename, Salop, but warned it could be months before a conclusion was reached.

A Sussex Police spokesman said: "We have identified lines of inquiry but these things take time.

"We are in contact with the family and keeping them abreast of developments. There are a number of officers and staff reviewing the case and working on lines of inquiry."

Police on Tuesday met relatives of one of the victims, Nicola Fellows, to update them.

The family had been critical of the force for alleged lack of action but Nicola's uncle Ian Heffron said: "The meeting was very constructive and we feel they are much more positive."

Mr Heffron, 48 and a former policeman, said further meetings would be held.

Nicola's family is threatening to sue Russell Bishop, a former Brighton builder, in an attempt to link him to the crimes.

Bishop was cleared of murdering Nicola and her friend Karen Hadaway in Wild Park, Brighton.

He was jailed for life in 1990 for the attempted murder of a seven-year-old girl from Brighton at Devil's Dyke.

Nicola's family are considering a civil action to claim £15 from Bishop for damaging Nicola's clothes.

They have tried a similar action once before but the bid failed.

They are banking on the Government's Bill on the double jeopardy rule becoming law.

Currently delayed, the Bill would mean a person acquitted of a serious crime could be tried again provided compelling new evidence could be produced.

It is believed part of the Sussex Police inquiry involves new forensic tests.

Bishop, currently serving his time at Whitemoor prison, Cambridgeshire, is close to his first parole hearing.

It was to have been held in April but has been put back until later this year.

No date has been fixed.