Cambridgeshire Constabulary has been accused of lacking focus during the Soham murder investigation in a report by the police inspectorate.
Chief Constable Tom Lloyd criticised for being on leave
The force was commended for its initial response but was accused of losing momentum in the report by Her Majesty's Inspectorate of Constabulary (HMIC).
Cambridgeshire's chief constable came under fire for being on leave in the early stages of the investigation.
The force was also criticised in an inquiry led by Sir Michael Bichard.
While the Bichard inquiry focused on police conduct before murders, the HMIC report was concerned with the murder investigation itself.
'Error of judgement'
Sir Ronnie Flanagan, who wrote the report, praised the response of police on Sunday 4 August 2002 immediately after they had received the call that the girls were missing.
But much of the criticism in the report revolves around the following two days when this "good momentum" was lost.
He said: "When details of the incident were recounted to the on-call senior officer covering the area, a decision was made which effectively resulted in nothing further
being done until officers reported on early [Monday] shift.
"In my opinion, this was an error of judgement."
Although a major incident room was set up and a dedicated team brought in on Tuesday, the reports cites a "lack of grip" on the investigation at a strategic command level on that day.
But Sir Ronnie stressed that after Tuesday there had been "excellent policing" leading to the arrests of Ian Huntley and Maxine Carr within 13 days of the murders.
Tom Lloyd, chief constable of Cambridgeshire police, was singled out for criticism for not returning from holiday until 10 days into the investigation.
"The chief constable readily accepted that his continued absence on leave was an error. I agree.
"His absence did not lead to any loss of evidence or impair the specific investigation although it was the source of critical media and public perception," the report stated.
Staff training in management of 'critical incidents'
Clarification of command structures
Enhancing pooling of resources between forces
Single point of contact for specialist advisers
Immediate decision on who is the senior investigating officer
Mr Lloyd, who earlier apologised for his force's role in failing to do adequate checks on Huntley before the murders, defended himself against the criticism in the HMIC report.
"Sir Ronnie Flanagan had told me that he had every confidence in the constabulary and the chief constable in terms of the best practice demonstrated by the Soham investigation and in terms of the chief constable's ongoing leadership of the force," he said.
The HMIC is part of the Home Office although it produces independent reports on the performance of police forces.