Hint : S.A.C.
The tactics echoed the approach the F.B.I. had used to dismantle the New York Mob. The plan was to arrest low-level soldiers, threaten them with lengthy jail terms, and then flip them, gathering information that could lead to arrests farther up the criminal hierarchy.
Over time, agents produced an organizational chart with names and faces, just as they had with La Cosa Nostra.
At the top of the pyramid was Steven Cohen.
It took me quite some time to read this gigantic piece, but as always, The New Yorker delivered a brilliant investigation. Here is another one from Vanity Fair.