Sorry Phil, that contention is so unproveable it is amazing you are still pushing it. There is absolutely no proof. Yes I have seen the many of the films, read the articles, and listened to the presentations of several groups claiming to have absolute proof.
Yemen's Houthi rebels commit to peace plan in letter to UN chief, BBC reports (Haaretz)
from the article: Reputed 9/11 mastermind says he decapitated journalist Daniel Pearl