The Independent Police Complaints Commission will investigate how intelligence concerning the movements of Peter Chapman while he was wanted for breaching the conditions of the Sex Offenders Register was dealt with by three police forces.

Chapman, a convicted sex offender, was jailed for a minimum of 35 years on Monday 8 March 2010 for the murder of 17-year-old Ashleigh Hall in County Durham in October 2009.

The independent investigation follows a joint referral from Durham Constabulary, Cleveland Police and North Yorkshire Police relating to the Automatic Number Plate Recognition (ANPR) systems used by the forces.

ANPR systems use fixed or in-car cameras to read number plates and identify any matches with information on police computer systems. Whenever a camera makes a match it is flagged up as a ‘hit’ on police computer systems.

Chapman’s vehicle, a blue Ford Mondeo, was circulated on the Police National Computer on 23 October 2009 in relation to allegations of theft, arson and failing to notify his change of address in line with his sex offenders’ registration.

The three police forces have identified ANPR records showing that Chapman’s car was in the force areas between 23-26 October 2009. Cleveland Police recorded 12 ANPR ‘hits’ over the three days, Durham Constabulary recorded two ‘hits’ on 25 October and North Yorkshire recorded two ‘hits’ on 26 October. All the hits were recorded on static, roadside ANPR cameras.

The hits in the Cleveland Police area resulted in the arrest of Chapman, at which point he confessed to Ashleigh’s murder.

This new investigation is separate to the ongoing IPCC investigation into how Merseyside Police monitored Chapman.

IPCC Commissioner Nicholas Long said: "Ashleigh’s murder was a terrible tragedy and my deepest sympathies go out to her family and friends. It is clear there are a number of issues identified through the murder investigation which warrant further examination by the IPCC.

"The information about recorded hits on ANPR systems warrants an independent investigation to determine how the intelligence was dealt with. I appreciate police forces receive thousands of ANPR hits on a daily basis, but we will want to know how the police forces concerned monitored these systems to determine what can be learned and whether improvements can be made.

"This investigation has the potential to impact on forces around the country as ANPR has become a well used tool. It is significant that it was through the ANPR system that Chapman was caught by Cleveland Police.”

Mr Long added: "I fully appreciate Ashleigh’s family remain devastated by her loss and the information coming to light regarding Chapman must compound their distress. Sadly nothing we can do now can change what has happened but I hope our thorough investigation will ensure any lessons are learned.

”I have spoken to Ashleigh's family and they have asked for the media to respect their grief and privacy and not contact or disturb Ashleigh's mother, Mrs Andrea Hall, or members of her family."