DETECTIVES hunting letter bombers believe the explosive devices are the work of animal rights extremists.

Six letter bombs have been delivered across the country in recent weeks, including one to a Church Lawton house.

Leah Cain, aged six, escaped with superficial injuries after opening a package containing ball bearings and pins.

The other devices were discovered in Humberside, North Wales, the West Midlands, and two in North Yorkshire.

The North Yorkshire Police are co-ordinating the hunt for those responsible, targetting groups and individuals involved with animal right activities.

The force is also seeking the help of the Metropolitan Police Anti Terrorist Squad.