The jury in the trial of Ian Huntley who is accused of the murders of Holly Wells and Jessica Chapman has been told to put aside emotion and judge the case on its facts.
The girls went missing in August last year
The parents of the two girls were at the Old Bailey on Tuesday to see seven women and five men selected randomly as jurors from a shortlist of 25.
Holly and Jessica disappeared on 4 August last year, and their bodies were found almost a fortnight later close to the RAF base at Lakenheath in Suffolk.
The jury was told Mr Huntley, a former school caretaker, has denied the double murder of the 10-year-olds.
It was also told Mr Huntley's former girlfriend Maxine Carr, 26, who worked at the school the girls attended in Soham, Cambridgeshire, has denied two charges of assisting an offender and one of conspiring to pervert the course of justice.
Trial judge Mr Justice Moses told the jury: "The death of anyone, and perhaps especially children, gives rise to understandable concern and emotion.
"But the courtroom, this courtroom, is not the place for any expressions of emotion".
He called for cool calm consideration of evidence, uninfluenced by sympathy.
"The essential duty we owe to the community is to ensure this is a fair trial."
He said it would be "idle to pretend" jurors had not read about the case or seen stories about it on television but warned they must be impartial.
"It means that you try this case on the evidence you hear and see in this
court, uninfluenced, unprejudiced by anything you may have heard, read or seen elsewhere, or anything that you may hear, read or see in the future".
"That is not evidence and it never becomes evidence.
"You and you alone are the judges of the facts as revealed by the evidence which will be called in this court".
Mr Huntley and Ms Carr have been held in custody since their arrests on 17 August last year.
Stephen Coward QC will defend Mr Huntley and Ms Carr will be represented by Michael Hubbard QC.
The trial was adjourned until Wednesday when the prosecution will deliver its opening statement.
The case is expected to last three or four months.