IT IS THE RATE OF OLD SPYMASTERS—like old spies—never to be thought to have died or vanished of natural causes. So when a canoe belonging to former CIA director William Colby was found capsized in Maryland's Wicomico River on April 28, conspiracy theorists had their suspicions at the ready. "It may have been an accident," says Joseph Trento, author of Widows, a Cold War history. "But this is a guy who had enemies because they thought he shot off his mouth to Congress."

Dusk was falling on Saturday, April 27, winds were brisk, and Colby, 76, was tired. But speaking by phone from his cottage in Cobb Island, Md., he had told his wife, Sally, 51, a foreign aid official who was at a conference in Houston, that he was going canoeing anyway. The next day a neighbor found his beached canoe. When another checked the cottage that evening, he found Colby's radio and computer still on, and dinnerware and a glass of wine on the counter. Colby, though, was missing.

Authorities immediately launched a search for the onetime spymaster, presumed to have drowned. Born in St. Paul, Minn., and Ivy League-educated (Princeton '40 and Columbia Law), Colby served with distinction in World War II with the clandestine OSS before joining the newborn CIA. There the efficient, owlish bureaucrat rose through the ranks to be named director by President Nixon in 1973. Yet with the CIA under scrutiny for its role in Watergate, Colby broke the code of silence, cooperating with Congress to expose agency misdeeds—including domestic spying—explaining later that he did so out of a firm belief in the Constitution. Many in Congress admired that; some CIA lifers did not.