It was a dull and steamy Monday in July. I was tossing spit-balls into a wastebasket across the room when the chimes on my ISDN 6508 communicator rang out. A red light blinked on the unlisted line. I activated the No-Eavesdropping system and lifted the receiver. DT 2 -- known to the family as Deep Throat Jr. -- was more terse than usual.

"A18, 6/11," she wheezed. "Spooks. Follow the stones." Click.

"Wait, DT! Wait!," I cried while activating the call tracer. Too late. She had zapped the 6508 with her Portable X220 Trace-Me-Not, which, by the way, is illegal in Nebraska.

I studied the message, consulted the code book and, by lunch time, had figured out a clue. A18 was a page number in The Post; 6/11 was the 11th of June. A check of the newspaper for that day confirmed my hunch. A story on A18 was headlined: "CIA Linked to Mandela's Arrest." With help from Dick Tracy, the "spooks" reference became clear: "spooks" are spies, some of whom are alleged to have been associated with the CIA.

The story said an anonymous, retired U.S. "intelligence agent" had spilled the beans about a CIA operation in South Africa that led in 1962 to the arrest of the fugitive "Black Pimpernel" -- Nelson Mandela. I noted that The Post article was not, technically speaking, an original piece of work. Rather it was a rewritten version of a story that had been splashed the day before on the front page of the Atlanta Journal-Constitution and had appeared four years before that in French and South African papers. (We often borrow from one another, you know.) This was the tale:

A CIA informant was a member of the Communist Party cell in Durban and was a confidant of Mr. Mandela, who was then wanted by the police on various charges. The informant notified his CIA case officer -- who may have been Donald Rickard or may have been Millard Shirley -- that Mr. Mandela would be in a certain place at a certain time on Aug. 5, 1962. This information was passed to the South African authorities who seized Mr. Mandela in his disguise as a white man's chauffeur. He spent the next 27-plus years in prison.

Within hours of Mr. Mandela's arrest, Paul Eckles, a senior CIA official in the South African station, boasted to a colleague that it was "one of our greatest coups." The colleague thereupon complained about the CIA's role in the affair to a State Department official, Henry J. Tasca, who took steps to prevent a recurrence of such activity. And it is this colleague, now a "retired intelligence officer" who told the story to the Atlanta newspapers.

As I absorbed these details, I was baffled by DT's suggestion that I "follow the stones." Eventually I got it: these were headstones, DT's metaphor for death and secrets carried to the grave. Mr. Eckles, Mr. Shirley and Mr. Tasca are all deceased. Mr. Rickard is retired and mute. The CIA turns aside all queries. So how does one confirm the account of the nameless "retired intelligence officer"? Where, as we say, is the "second source"?

The Atlanta reporters, Joseph Albright and Marcia Kunstel, found a retired South African intelligence officer, Gerard Ludi, who has told several stories to the press. In one interview he fingered Mr. Shirley as the villain of the piece but told The Post he had no knowledge that the CIA had engineered the Mandela arrest.

The South African press reported in one piece that when captured Mr. Mandela was en route to a rendezvous with agent Rickard. A rendezvous for what purpose? Another story, based on police sources, said a U.S. diplomat in Pretoria in 1962 -- not the CIA -- brought about Mr. Mandela's arrest.

Old hands in the agency sniff at the whole tale. "We are left," a most reputable observer notes, "with a report from a source who refused to reveal himself but who identified a colleague and implied he was a political fool. It is corroborated by a source who evidently does not know what he is talking about and {is} alleged to be confirmable by another who is deceased. ... What are we to make of this?"

I wondered, too. But then a bolt from the blue: a message, via the trusty 6508, from DT 3, who undoubtedly had some knowledge of the affair. "There is more to this than meets the eye," he reported.

More of what? More on a possible Mandela connection? More on the CIA? More on State?

The Almighty knows. She sayeth not, and I'm confused.