Number of people either found guilty of involvement in 9/11 hijackings or currently charged now totals: Zero

By Charlie Savage, Globe Staff | May 4, 2006 WASHINGTON -- A federal jury yesterday spared Zacarias Moussaoui from a death sentence, deciding that the only person charged in connection with the Sept. 11, 2001, terrorist attacks should instead spend the rest of his life in a US prison. . . .

Investigators had initially suspected that Moussaoui was intended to be the ''20th hijacker" . . . .

Investigators eventually decided that the intended 20th hijacker was instead Mohamed al-Qahtani, a Saudi who . . . was later captured and is held at the Guantanamo prison.

Moussaoui, 37, is an admitted member of Al Qaeda who has said he wanted to kill Americans. But the discovery of Qahtani cast uncertainty over Moussaoui's role in the Sept. 11 plot. It is a mystery that, despite his guilty plea and yesterday's verdict, his trial did not resolve.