A schoolboy who threatened to carry out an Islamic State-inspired vehicle attack on the day of a Justin Bieber concert has been found guilty of five terror offences.
The 17-year-old, who cannot be named because of his age, was arrested in June after searching the internet for details of security at the Canadian star's world tour show in Cardiff.
The boy, who hid a hammer and knife in his school bag and wrote a "martyrdom letter" after being radicalised online, was convicted of preparing for terrorist acts following a nine-day trial at Birmingham Crown Court.
Jurors unanimously convicted the teenager, from Rhondda Cynon Taf, of two counts of encouraging terrorism by posting extremist material on Instagram, and two charges of possessing Isis propaganda magazines.
The panel deliberated for four hours and 19 minutes before also convicting the boy by an 11-1 majority verdict of preparing for terrorist acts.
The youth, of a white British background, was arrested at his home by police on June 30 - several hours before Bieber took to the stage at Cardiff's Principality Stadium.
At the start of the boy's trial it emerged that he had written a note apparently aimed for distribution after his death reading: "I am a soldier of the Islamic State and I have attacked Cardiff today because your government keep on bombing targets in Syria and Iraq.
"There will be more attacks in the future."
The note - found with the gutting knife and claw hammer - also featured bullet points including "run down the non-believers with a car" and "strike the infidels, who oppose Allah, in the neck".
Opening the case against the boy at the start of the trial, prosecutor Matthew Brook told the jury of seven men and five women: "In this case, the evidence will prove that he became radicalised over the internet.
"He had terrorist material stored on his computer, he published posts on Instagram which encouraged terrorism and he was planning a 'lone wolf' style attack in the name of Islam."
Cardiff's Castle quarter was among the areas researched by the boy using Google maps, while other searches sought details of a shopping centre, the city's Central Library and the New Theatre.
Further web searches presented to the court included "vehicle mounting pavement" and "car ploughs through a crowd".
The boy told police he took a knife and a hammer to his school on the day of his arrest but claimed he had no thoughts of using either weapon in a terror attack.
Remanding the boy in custody until a sentencing hearing on January 10, Judge Mark Wall QC told defence barrister Delroy Henry: "The offences for which he has been convicted obviously merit a significant custodial sentence. One of the things I will have to consider is whether there ought to be an indefinite sentence. I need as much information on him as you wish to place before me."