President Richard Nixon in the oval office, 1971. His administration bugged everyone – including the president himself. (Nation Archives)

One morning in early March 1971, Army counterintelligence agent Dave Mann was going through the overnight files when his eyes landed on something unexpected: a report that a routine, nighttime sweep for bugs along the Pentagon's power-packed E-Ring had found unexplained – and unencrypted – signals emanating from offices in the Joint Chiefs of Staff.

Someone, it seemed, was eavesdropping on the top brass.

Mann was no stranger to bugs. It was a busy time for eavesdroppers and bug-finders, starting with the constant Spy vs. Spy games with Russian spies. But the Nixon years, he and everyone else would soon discover, had extended such clandestine ops into new territory: bugging not just the Democrats, but people within its own ranks. Eventually, most of the Watergate-era eavesdropping schemes were revealed to the public, including the bombshell that Nixon was bugging himself. But the bugs Dave Mann discovered in the E-Ring in March 1971 – and another batch like it – have remained buried all these years. Until now.

To understand how crazed this era really was, it helps to remember that the Nixon White House was obsessed with not just secrecy, but skullduggery. Only months into the new administration, in 1969, the chairman of the Joint Chiefs of Staff was so freaked out by the back-alley dealings of Henry Kissinger that he put a spy in the White House to steal documents from his briefcase. Kissinger in turn was bugging his own staff and other officials, including one in the office of the Secretary of Defense.

All this was two years before the so-called White House Plumbers, led by ex-CIA agent Howard Hunt, were busted in the Watergate offices of the Democratic National Committee, eventually opening a window into the Nixon funhouse. More than 50 people in the Nixon White House were working on dirty tricks to discredit political opponents, Bob Woodward's infamous "Deep Throat," himself a senior FBI official up to his armpits in illegal bugging operations, would whisper in one of their freaky late-night garage meetings. "Everyone's life," he warned the reporter, "is in danger."

But "the White House horrors," as they became known, were still only wisps of suspicion outside Nixon's circle when Mann made his discovery.

Army Chief of Staff Gen. William Westmoreland twice suspected that his office was bugged. (National Archives)

The signals were eventually tracked to the offices of Gen. William Westmoreland, chief of staff of the United States Army. The guys on the Technical Surveillance Countermeasures team, or TSCM, wrote up a report.

Mann, now 67 and semi-retired in Tennessee, was on duty the next morning with the Pentagon Counterintelligence Force, a unit compartmented from the TSCM and so secretive that it has managed to escape public notice until now. He and his PCF partner, Tom Lejeune (who would later be killed in Vietnam), undertook an investigation.

"We went up to the office and entered one of the telephone closets, which line the halls of the various Pentagon corridors," he tells Danger Room. "In the one across from Westy's office, we found that we were able to recover audio from his office by the simple method of placing a handheld amplifier on … the wires going to the office suite."

"Tom noticed that there were two terminals which were slightly apart from the normal ones," Mann continues, "and which had a pencil mark on each and the word ‘Westy' written in pencil. That was where pure [unencrypted] audio emanating from the open carbon microphone inside the telephone handset was coming from. It was like having an open, high quality broadcast microphone in the office on all the time.”

"Someone had figured out that they could obtain clear room audio without the risk of a clandestine listening device or other more obvious tampering to the telephone," Mann adds. "It also told us that whoever did the job had to have access to the telephone and to the actual telephone closet."

They clipped headsets to the ‘Westy' line to record a sample.

"We both heard and recorded for posterity a diatribe by General Westmoreland royally chewing the ass of some unfortunate underling," Mann recalls with a chuckle.

They also found Westmoreland's military assistant's phone wired for sound, Mann remembers. And three more in the E-Ring: in the offices of the Army's assistant chief of staff for logistics; an assistant secretary of the Army, Barry Peixoto; and another belonging to a general's whose name he can't remember.

When Mann and Lejeune presented their findings, an investigation was launched, code-named GRAPPLE TRIP.

These Chapstick tubes with hidden microphones were one of many bugs on display at the trial of the Watergate burglars. (National Archives)

Mann suspected the bugging – if it was that – would have been done by either a member of the PCF TSCM crew itself or an employee of the Chesapeake and Potomac Telephone Company.

"Lots of fingers pointed towards the Chesapeake and Potomac Telephone Company and a certain retired FBI agent who was their head of security liaison," Mann adds by e-mail. "It was pretty well known that C&P Telco was J. Edgar [Hoover]'s go-to bunch."

True, that. The technique Mann described – activating carbon mics in the phones – was a common FBI bugging technique, two former agents confirmed on condition of anonymity, without commenting on Mann's specific discovery. They called them "PL drops."

Only later, after the Watergate scandal exploded, did the world learn that the FBI was, in fact, bugging at least 17 people on behalf of Kissinger. They included Air Force Col. Robert Pursley, an aide to Defense Secretary Melvin Laird, four journalists, and 13 of Kissinger's own aides or State Department officials. Ostensibly, the goal was to plug leaks of internal deliberations about the secret bombing of Cambodia and other subjects.

According to a May 12, 1973 internal FBI memoranda (.pdf), the Kissinger bugs were "a super-sensitive matter and no record [was] to be maintained on these wiretaps." To further help cover their tracks, "there would be no written record at the Chesapeake and Potomac Company concerning the above-noted wiretap requests."

Which shows, of course, that the FBI routinely did rely on C & P in and around Washington for "PL drops," as Mann says. But it also suggests that the signals Mann and Lejeune found emanating from Westmoreland's suite were not part of the Kissinger project.

While digging into those mystery bugs, however, Danger Room found another.

In 1969, not long after the one-time Vietnam commander was kicked upstairs as Army chief of staff, Westmoreland was overseeing a number of sensitive investigations into corruption in the Army.

One probe was of heroin being smuggled back from Vietnam in caskets. Another centered on a "Little Mafia" of senior NCOs, that was skimming cash out of military service clubs in Vietnam. A third was targeting the Army's former top cop, who was suspected of reselling weapons recovered by National Guard troops during the 1960s domestic riots.

Westmoreland, according to Fred Westerman, a member of the Pentagon Counterintelligence Force in 1969, was "bent out of shape" by minute details of his investigations showing up in The Washington Post and The New York Times. Suspecting they were coming from inside his own offices, he demanded that the PCF dispatch a Technical Surveillance Countermeasures Team to check his phones for bugs.

In an eerie preview of what Dave Mann and Tom Lejeune would find two years later, Westerman's TSCM team detected audio signals being broadcast from a phone in Westmoreland's suite.

Nixon and Henry Kissinger, pictured with Don Rumsfeld at a 1974 NATO neeting. (NATO)

"I can't say we found devices, but there was enough concern that it was shipped off for evaluation" to the 902d Military Intelligence Group, parent unit of the PCF, and then further up the chain to an inter-agency group,Westerman said. Because of strict compartmentalization of information between the two, he never did find out who the culprit was – if any.

"Much ado about nothing," says retired Army Lt. Col. Robert W. Loomis, the PCF's operations officer in 1971. Now a psychologist in Pickens, S.C., Loomis said he remembered the GRAPPLE TRIP investigation well.

"Nothing came out of it," he said in a telephone interview. The audio broadcasts by the phones in Westmoreland's suite, he said, were a result of "crossed wires in the telephone system." The lines were "traced out" and "the final determination was that the signals never left the Pentagon." The reason that the investigation was so hush-hush, he said, was that some of the lines went "directly to the White House," which brought the Secret Service into the case.

"As far as I recall, the signals that were found never went further than the E-Ring of the Pentagon," Loomis said.

"Well now, that's a good story," responds Dave Mann. "I am still of the opinion that someone was doing the listening." In his long career in the counterintelligence world's wilderness of mirrors, he says he often found bugs planted in intelligence facilities by other intelligence units.

"There was a lot – and I mean a lot – of pressure to prove GRAPPLE TRIP to be a fluke or a miswired telephone," he adds.

"It seemed at the time to those of us at the investigator level that the [four apparent bugs found in the E Ring] were connected," Mann continues. "Each of those offices were in some way connected to the bombing of Cambodia and other secret operations against the North Vietnamese."

Westmoreland was likely out of the loop on those ops. But as Army's boss, sitting around the E-Ring table with the chiefs of the Navy and Air Force, he was still a member of one the world's most powerful small clubs – and a White House rival.

"The Nixon administration was undoubtedly the most untrusting of any in our history – and they often tapped government officials because they suspected they were being spied on. In the case of the JCS, at about this time, that happened to be the case…." says Mark Perry, author of "Four Stars," a highly praised 1989 history of the Joint Chiefs.

Dave Mann says the truth will probably never be known.

Years after the original incident, he returned to duty at Pentagon Counterintelligence Force, still curious about it. He ordered up the GRAPPLE TRIP case file, which was "about a foot high and included the tapes we had made."

In the "last few pages of the files," he says, he found the conclusion: "Persons unknown had accidentally modified the telephone instrument."

"At the end of the day," he adds, "we will never know for certain who was responsible, and if there was intent or not."

See Also:- Wired 10.07: Richard Nixon's Last Secret