The jury in the Soham murder trial has been sent home after about five hours of considering its verdict.
The judge said a unanimous verdict must be reached
Ian Huntley, 29, admits Holly Wells and Jessica Chapman died at his house and that he disposed of their bodies, but denies murdering them.
His former girlfriend Maxine Carr, 26, denies conspiring to pervert the course of justice and two counts of assisting an offender.
The jury was sent home for the weekend at about 1615 GMT by Mr Justice Moses.
He told the jury to stop deliberating about the case among themselves and not to discuss it with anyone.
He also warned them to "be careful" about reading press reports on the case during the weekend.
They will be recalled on Monday at 1030 GMT, the judge told them as the parents of both girls sat in the court with Holly's brother Oliver, 14, and Jessica's sisters Rebecca
and Alison, aged 18 and 15.
The jurors had started their deliberations just after 1100 GMT, after the judge had concluded his summing up and told them to appoint a foreman.
He said they must reach a unanimous decision.
During the day's deliberations the jurors had requested to again see the bath from Mr Huntley's house which was shown during the trial.
The 10-year-old schoolgirls disappeared from their village of Soham, Cambridgeshire, on 4 August last year. Their bodies were found two weeks later.
Earlier, the judge concluded his summing-up, which he began on Thursday, by reviewing the evidence regarding Ms Carr.
The court has heard that Ms Carr admits lying to police to provide an alibi for Mr Huntley.
But she denied she even suspected her boyfriend had been involved in the girls' deaths.
Mr Justice Moses told the jurors they must decide whether Ms Carr lied
for him knowing or believing that he killed the girls.
He reminded the jury to examine her evidence carefully, saying they must bear in mind that she might want to make Mr Huntley's situation worse and hers better.
The judge warned that it would be "unfair" to Mr Huntley to
speculate on the nature of the relationship between him and Ms Carr.
He said Mr Huntley had told Ms Carr shortly after they met about a time he was falsely accused of rape, and the effect that had had on him.
Ms Carr had said she loved Mr Huntley
"very, very much".
She had also known Holly and Jessica and had said they were "lovely girls" and
the kind of daughters she would have wanted to have, he said.
Ms Carr had left the house in Soham on the Saturday before the girls vanished to
see her mother in Grimsby - and left it "very, very clean".
The girls went missing in August last year
Holly and Jessica's badly-decomposed and burnt bodies were discovered in a ditch on Lakenheath RAF base on 17 August 2002.
During the trial, Mr Huntley told the court Holly died accidentally, after falling into his bath as he helped her with a nosebleed.
But he admitted killing Jessica by putting his hand over her mouth to stop her screaming.
The judge stressed to the jury the fact Mr Huntley had dumped the girls' bodies in a ditch did not mean he had murdered them.
He said the jury could
return verdicts of murder or manslaughter on either or both girls; of
manslaughter by gross negligence in the case of Holly; or not guilty of
killing either girl.
The judge warned the jurors not to be influenced by the press or emotions roused by the case, and to judge it on the evidence alone.