POLICE investigating the sending of a series of letter bombs, including two in Oxfordshire, have been given more time to question a 27-year-old school caretaker.
Miles Cooper was arrested at his home on the outskirts of Cambridge at about 3am on Monday following a large-scale investigation.
Police said a magistrate had given officers permission to continue questioning Mr Cooper until 4pm today.
Forensic experts continued to search Mr Cooper's home in Cherry Hinton, and the nearby Teversham Church of England Primary School where he works.
A woman sustained a minor injury when a device ignited at Orchid Cellmark in Abingdon. Another device sent to LGS Forensics in Culham was intercepted.
Detectives said a total of seven letter bombs were sent to addresses in southern England, the Midlands and Wales. Nine people were injured in explosions after packages were opened.
Officers say devices were homemade and contained in A5 padded envelopes.
In January, a device was sent to The Forensic Service in Birmingham in addition to the two in Oxfordshire.
And earlier this month, devices were sent to other firms with links to traffic enforcement including the Driver and Vehicle Licensing Agency in Swansea, the London offices of Capita, the firm involved in the administration of the congestion charge and an accountancy firm in Wokingham, Berkshire, that deals with mail for Speedcheck - a company which supplies traffic regulation devices.
A device was also sent to a house in Folkestone, Kent.