Ramzi Binalshibh, as know as one of the masterminds behind the 9/11, "The Office of the Director of National Intelligence described him as a "key
facilitator for the terrorist attacks on September 11, 2001" according to Wikipedia. As of today according to Wikipedia Ramzi Binalshibh is a
detainee at Guantanamo Bay.
Link
The WSJ article doesn't say that Ramzi Binalshibh, who is in US custody, was killed in a drone attack but that Naamen Meziche, who had contact with
Ramzi years ago, was.