The Federal Bureau of Investigation maintains more than ﬁfteen thousand “conﬁdential human sources.” The Drug Enforcement Administration has its own tipsters, as do the Secret Service and the Bureau of Alcohol, Tobacco, Firearms, and Explosives; over all, the Justice Department pays informants as much as a hundred million dollars a year. Trained agents like Grimm generally create new identities for their jobs, and spend months or years building up connections and gaining the trust of criminals. Conﬁdential informants like von Habsburg simply operate within their normal lives.
Informants are especially valuable because they can collect evidence that would require court orders if they were government agents. In almost every successful case against a large-scale criminal enterprise—from the one against John Gotti’s Mob operation to those involving terrorists plotting against New York synagogues and subways—an informant has played a central role. “The human-source program is the lifeblood of the F.B.I.,” an assistant director of the Bureau told a congressional hearing in 2007.