FBI foils massacre plan at Northamptonshire school......

A British teenager's plans to carry out a massacre at his school using handguns and explosives was foiled by the FBI after agents received a tip-off from an American chatroom user, a court has heard.

The 16-year-old drew up detailed plans to massacre his classmates in Northamptonshire using handguns and home-made bombs.

He created intricate classroom plans and a hit-list of fellow students and where they sat, and said he would carry on shooting until the police arrived, at which point he would take his own life.

But after warning users on a forum that he would be armed and ready "20 minutes from now", one user called the FBI, who alerted police in England.

On Monday the boy, who cannot be named because of his age, was detained indefinitely in a secure mental unit after admitting possessing explosive materials and possessing terrorist materials.

Birmingham Magistrates were told that the teenager suffers from Aspergers syndrome, stockpiled terrorist e-books and guides to making explosives on his computer.

When police searched his home they also found chemicals used to make explosives which had been bought from the internet.

He was arrested in February last year after detailing his plans on the anonymous chat website 'Omegle', claiming he would carry out the massacre in revenge for being bullied at school.

Prosecuting, Mark Topping said an American chat room user had alerted the FBI when the boy had made comments about carrying out the mass killing on February 24, who contacted police in England.

He said: "The boy told the person he was going to stage a massacre at his school using handguns then committing suicide.

"He said 20 minutes from now he would be armed with a Magnum .44 revolver, a Beretta 92FS and various other weapons and ammunition.

"He said he would keep shooting until the police arrived, at which point he would commit suicide.

"He also made a comment about how people shouldn't have bullied him so much."

Mr Topping added: "He spent some time looking for this material and wrote out a quotation on a notice board at school which was quickly erased.

"The recoveries included diaries and notebook instructions for the construction of IEDs.

"There were further notes about plans for the massacre.

"There were plans of class rooms, desks at which pupils sat and who was to be targeted.

"It is interspersed with references to [the boy] feeling himself to be weak and powerless, excluded from social activities and being bullied."

A police search of the teenager's home found 20 publications, including 'The Terrorist Handbook', 'The CIA Explosives for Sabotage Manual' and bomb-making guide 'An Anarchist's Cookbook - Recipes for Disaster'.

The court heard that police also found diaries and hand-written notes containing detailed plans for the massacre and research on 'Lone Wolf' killers including Black Panther Donald Nielsen. The notes were "interspersed with references to [the boy] feeling himself to be weak and powerless, excluded from social activities and being bullied".

Officers also found sealed containers of potassium nitrate and sulphur powder - 'precursor chemicals' for gunpowder - which the boy had bought online using his father's PayPal account.

Dr John O'Brien, the boy's psychiatrist, said that the boy's disorder caused him to obsess over his interests.

He added: "He has talked about this in a fantasy-type way, and has said he never planned for it to be real life and he didn't have plans to carry it out. He knew it was a crime and was wrong."

Imposing a hospital order, District Judge Howard Riddle said evidence from medical experts provided "hope" for the boy's future.

He said: "I think I speak for everyone when I say we all wish you well."

The boy also admitted a third charge of possessing 'Lollicon' images - Japanese cartoons depicting child sex abuse