A primary-school caretaker has been charged in connection with a series of letter bombs sent to offices linked to traffic enforcement in Britain, police said Thursday.

Miles Cooper, 27, will appear Friday at a Magistrates Court in Banbury, west of London, to face charges of 12 offenses under explosives and assault laws, the Association of Chief Police Officers said.

Cooper was arrested Monday near Cambridge, 55 miles (89 kilometers) northeast of London.

Nine people were injured in seven letter bomb attacks, police said. The last three attacks, which occurred over three days, drew national attention.

On Feb. 5, a woman was injured by an exploding parcel at the head office of Capita Group PLC in London. One of the company's many government contracts is for designing and running a system for enforcing the 8-pound (euro12, US$16) daily congestion charge imposed on motorists in central London.

Two people were injured Feb. 6 in an explosion at Vantis PLC in Wokingham, 40 miles (65 kilometers) southwest of London. The accounting company reported the package was addressed to a client. Police said the company's clients include Speed Check Services, which provides traffic monitoring technology.

The next day, three people were treated after a parcel bomb exploded at the headquarters of the Driver and Vehicle Licensing Agency in Swansea, Wales.

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