A 17-year-old has been jailed for life for planning to bomb a Justin Bieber concert in Cardiff, Wales, on behalf of ISIS, one month after the deadly 2017 Manchester terror attack on an Ariana Grande show. Prosecutors said Lloyd Gunton researched the security of the Bieber concert and wrote a “martyrdom letter,” which reportedly 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.” Authorities said Gunton was apprehended at his home in South Wales the day of the concert, where police found a “claw hammer and a gutting knife” in his backpack. The prosecution also told the U.K. jury that Gunton wrote out a plan, with bullet points that included “run down the non-believers with a car” and “strike the infidels who oppose Allah in the neck.” On the stand, Gunton denied he actually believed in Islam, saying, “I wanted to see how easy it was for people who had an interest in terrorism to go online and get information... I wanted to see if it was possible, not for me, but from someone else’s point of view.” He will have to serve 11 years in prison before being eligible for parole.