Jurors considering the case of a British teenager accused of planning an attack on his old school in a repeat of the Columbine massacre have failed to reach a verdict for the second time.
Prosecutors said Michael Piggin, 18, kept petrol bombs, air rifles, pistols and armour at his home to use against staff and pupils at his former high school in Loughborough, Leicestershire.
Police discovered the stash when they were called to investigate a public order offence from six days earlier at his home in Beaumont Road, Loughborough, in February last year.
Piggin and two other teenagers, who cannot be named, had admitted charges of possessing petrol bombs and component parts of pipe bombs for the use of explosive devices, the jury was told.
He has also admitted possessing the component parts for improvised explosive devices (IEDs).
But Piggin, who has Asperger's syndrome, pleaded not guilty to two charges under the Terrorism Act.
He denied possessing items for the purpose, preparation and instigation of an act of terrorism and possessing a document or record containing information likely to be useful for a person committing or preparing an act of terrorism.
He faced a retrial at the Old Bailey after an earlier jury could not decide on a verdict.
The fresh jury of six men and four women which had been deliberating since May 13 were also discharged after they told the court they were unable to decide.
Prosecutor Gareth Patterson indicated the Crown would not be seeking a further retrial saying: "If this jury cannot return verdicts that will be the conclusion of proceedings."
The teenagers are expected to be sentenced at the Old Bailey on June 13.
The Columbine High School massacre of 1999 was one of America's worst mass shootings. Eric Harris and Dylan Klebold murdered 12 students and a teacher at the school in Colorado before both committing suicide.
Piggin's defence lawyer later asked that his client be formally cleared of the terror charges, in light of the prosecution's indication that there would be no third trial.
Ali Naseem Bajwa QC said: "The second jury to try Michael Piggin was unable to reach a verdict after 66 hours or so of deliberation and it was only right the jury should be discharged from returning a verdict."
He said the court should take account of Piggin's age and state of "anxiety" and "clear the decks if at all possible".
Given the amount of publicity the two trials attracted, he said the media should now be able to report not that the jury failed to reach a verdict, but that the teenager had been cleared.
But prosecutor Max Hill QC said the two counts should correctly be ordered to lie on file connected with the charges that Piggin has admitted - or the Crown could offer no evidence.
He said there was "no magic" to saying Piggin had been formally cleared and the prosecution had no intention of going back on its word.
The court heard that psychiatric reports would be prepared ahead of the sentencing date.
The Recorder of London, Brian Barker QC, declined to give his decision immediately, but told Piggin's defence: "I quite understand the necessity to look at this and I understand your client would like to as it were clear the decks."
He agreed to look at the issue again on June 13.