The case of the Venezuelan cocaine is the only known instance in which the agency has acknowledged that its actions led to drugs being imported into the United States.

When news of the cocaine shipment broke in November 1993, Kent Harrington, then the chief spokesman for the C.I.A., called the matter ''a most regrettable incident,'' and characterized it as a serious accident. No C.I.A. official has been charged in the case, and there is no evidence that anyone at the agency profited from sales of the drugs.

An agency spokesman said he had nothing to add today.

The Venezuelan National Guard unit headed by General Guillen and sponsored by the C.I.A. was one of several anti-drug units set up by the intelligence agency in the late 1980's with the cooperation of Latin American and Caribbean armed forces.

From 1987 to 1991, the years General Guillen was in charge, the unit placed a spy in the ranks of a Colombian drug cartel and began trying to win the confidence of drug lords by handling shipments totaling 22 tons of cocaine being shipped through Venezuela. The Venezuelan National Guard is a paramilitary force that controls the nation's borders.

In December 1989, Mr. McFarlin and the C.I.A.'s station chief, Jim Campbell, who is now retired, met with the Drug Enforcement Administration's attache in Venezuela, Annabelle Grimm, to discuss an ''uncontrolled shipment'' of cocaine to the United States that the C.I.A. said would help it learn more about the Colombian cartel.