A man who was charged over letter bombs sent to addresses in England and Wales has been remanded in custody.
Mr Cooper was arrested at his home on the outskirts of Cambridge
Miles Cooper, 27, a school caretaker from Cambridge, faces 12 charges under the Explosive Substances Act and the Offences Against the Person Act.
He appeared at Banbury Magistrates' Court in Oxfordshire in connection with seven devices posted over three weeks.
Nine people were hurt in the attacks in London, Swansea, the West Midlands, Berkshire, Kent and Oxfordshire.
Mr Cooper was arrested at his home in Cherry Hinton, on the outskirts of Cambridge, on Monday.
He was remanded in custody until his next appearance at Oxford Crown Court on 2 March.
No plea was entered.
Forensic experts have been searching Mr Cooper's home as well as the nearby Teversham Church of England Primary School where he works.
Anton Setchell, the Association of Chief Police Officers' national co-ordinator for domestic extremism, said the letter bomb investigation, Operation Hansel, was "progressing well" and would continue for many weeks.
He added: "I am now satisfied that there are no other postal packages connected to this inquiry that will present a danger to the public."
Seven of the 12 charges relate to the seven letter bombs; the other five charges relate to the people who were injured after opening them.
Four workers were injured when a parcel bomb exploded in the post room at the Driver and Vehicle Licensing Agency's main centre in Swansea earlier this month.
During the previous week, two men had suffered blast wounds to their hands and upper bodies in a "small explosion" at accountancy company Vantis in Wokingham, Berkshire, and a woman had been hurt in an explosion at the Capita office building in Victoria Street, Victoria, London.
The previous four bombs were sent to a private home in Folkestone, Kent, two companies in Oxfordshire and the Forensic Science Service in Chelmsley Wood, near Birmingham.