17-year-old Llantrisant, Wales native Lloyd Gunton has been handed a life sentence after being convicted of plotting a terror attack at Justin Bieber‘s June 2017 show in Cardiff. He will serve at least 11 years in prison before being given the opportunity for parole.

In November of last year, Gunton was found guilty of planning the foiled attack, which was set to take place just weeks after an Islamic State-inspired bombing claimed more than 20 lives at Ariana Grande‘s May 22nd concert in Manchester, England. As The Guardian reports, prior to Bieber’s Cardiff, Wales show, Gunton researched the security in place for the performance. He also penned a “martyrdom letter,” recovered when authorities raided his home on the day of the show. It read:

“I am a soldier of the Islamic State. I have attacked Cardiff today because your government keep on bombing targets in Syria and Iraq. There will be more attacks in the future.”

When they raided his home, police also found a backpack containing a knife and a claw hammer. According to The Guardian, jurors at Birmingham crown court, where the case was tried, were told Gunton had also written a note with bullet points including “run down the non-believers with a car” and “strike the infidels who oppose Allah in the neck.”

The defense for Gunton, who is on the autism spectrum, argued that the teenager was simply curious about the Islamic State (ISIS), and had no intention to actually carry out a terror attack. As The Guardian reports, “He told the jury he had a ‘stupid interest in the gory’ and was curious about ISIS, but claimed he had no intention of carrying out a terrorist attack…In the witness box, Gunton said he did not possess a copy of the Qur’an, did not believe in Islam and ate ham.”

As Gunton told the court during his trial, “I wanted to see how easy it was for people who had an interest in terrorism to go online and get information, because the police and the government are trying to crack down on terrorism and radicalization. I wanted to see if it was possible, not for me, but from someone else’s point of view.”

During sentencing, the judge did not let Gunton’s disorder affect his decisions, explaining:

Yours is not a condition from which you will recover… It is important that, having been tempted to commit a serious offence such as this, you are under some form of supervision for the rest of your life.

You can read the judge’s full verdict and sentencing explanation here.

[H/T The Guardian]