Along with Abu Walid al Masri, Saeed al-Masri and Saif al-Adel, al-Walid opposed the September 11 attacks two months prior to their execution.[5][2](p18)[7] Under interrogation, Khalid Sheikh Mohammed said that al-Walid had opposed any large-scale attack against the United States and wrote bin Laden a stern letter warning against any such action, quoting the Quran.[5]