My brother swears that the twin towers were felled by explosives placed there by the FBI. I've presented him with reams of evidence to the contrary, but he hasn't wavered.

我的兄弟坚信双塔是被FBI事先放置在里面的炸药炸踏的，我给他看了很多书面证据试图说服他，但他还是坚信不疑。