Forensics

Who lives, dies in attacks can give clues about terror cells

The bomb maker, the transporter, the landlord and the cipher. The four men slipped away after the Nov. 13 attacks in Paris, and all but one reappeared as key figures in the Islamic State cell that went on to attack Brussels.

Two are dead, one is captured, and the fate of the fourth remains a mystery.

Who lives and who dies in an attack can provide crucial clues to how terrorist cells are structured, demonstrating who is considered disposable and who is crucial for the next job. That status can be fleeting, as the two attacks show that someone considered vital in one operation may be sacrificed in another.

Some of the figures in the Paris plot had become "cannon fodder" by the time of the Brussels attacks, said Nicolas Henin, a journalist held hostage by Islamic State for 10 months.