en.wikipedia.org
1993 World Trade Center bombing
Emad Salem, an FBI informant and a key witness in the trial of
Ramzi Yousef,
Abdul Hakim Murad, and
Wali Khan Amin Shah, stated that the bomb itself was built under supervision from the
FBI.
[7] During his time as an FBI informant, Salem recorded hours of telephone conversations with his FBI handlers, and reports submitted in court. In tapes made after the bombings, Salem alleged that an unnamed FBI supervisor declined to move forward on a plan that would have used a "phony powder" to fool the conspirators into believing that they were working with genuine explosives.
[8]