Tiger Trap

by David Wise

  "They're going to be after you," Grove told him. "They'll be in touch. There's no such thing as a free lunch."

  Grove's prediction proved accurate. "We knew who had recruited him, and other students. Jerry Chen." The proprietor of the shop in Oakland, it seemed, was doing more than repairing televisions.

  A month later Tommy Tang returned to see Grove. "He said, 'These people want me to work in a bookshop collecting technical books to send to China.' He was busy with school work. He said, 'I don't know if I have the time.'"

  Grove considered the problem. "I said, 'If I pay you, will you do it?' He said, 'I will.'" After Tang agreed to collect the books, he showed them to Grove, so the FBI agent knew what materials were going to China. Soon afterward, Tang told Grove that Jerry Chen had called him and asked him to go to Beijing for the book project. Tang agreed to go. Which is why he was in Beijing at the precise moment when Hanson Huang was casting about for a secure way to deliver his letters to Gwo-bao Min. What better courier than a reliable student who would be passing through Hong Kong en route to Berkeley?

  Grove recalled what happened next. "He [Tang] was gone a week or a couple of weeks when I got a call on my home phone. 'Holy shit, Mr. Grove! You'll never guess what I have.'

  "He said, 'I got a letter for this guy at the Lawrence Livermore lab and I opened it and they want more information on missile guidance systems.'

  "The letter was addressed to Gwo-bao Min," Grove said. "It was a typical Chinese airmail letter where you undo the flaps to open it. He did, and I said, 'You probably ruined it.' He had opened it before he called me. He probably tore the flaps when he opened it. He bought another envelope and copied the letter; it was in Chinese script."

  The student told Grove that his copying the letter would not matter because the recipient would not know who originally wrote it. "He rewrote it in Hong Kong," Grove said. "He mailed the letter in Hong Kong as instructed by the Chinese. The kid brought the original letter back to me."

  Grove did not recall seeing the for-show, innocuous letter that also made its way to Min. But thanks to Dan Grove, and a bit of lucky timing, the FBI now had Hanson Huang's substantive letter. The bureau did not have to wait long to see how Min would react.

  After reading the letter, Min decided to deliver the answers in person to Beijing. He did not tell the lab, as required, that he planned to travel to China. His wife called his office at Livermore and said he was sick and would not be coming to work.

  Bill Cleveland then orchestrated an elaborate ruse in an effort to trap Min. As the engineer walked through the terminal at San Francisco International Airport, the public-address system blared an unusual announcement, reminding passengers that it was illegal to transport certain items. The long list of prohibited materials included firearms, explosives, and nuclear weapons information.

  As Min got in line to board his plane to Hong Kong, several FBI agents were, unknown to him, in the queue immediately ahead of and behind him. The passengers were told that all carryon luggage would be subject to a search by US Customs. Min's briefcase and the bags of his fellow "passengers" were taken to a room out of view.

  Inside his briefcase, the FBI found two index cards. On one card, in Min's handwriting, were the same five questions that Hanson Huang had posed in his letter. On the other card was the answer to the first question, about a method to measure the yield of hydrogen bombs when they were tested in the atmosphere. Since there were no written answers to the other queries, the FBI judged that Min already knew the answers without committing them to paper. But Min was not an expert on atmospheric testing; the FBI later discovered he had copied the answer to the first question about measuring the yield of hydrogen bombs from a classified document.

  The measurement technique was based on "Teller light," named for Edward Teller, a blue fluorescence caused by the interaction of gamma rays and air that can be detected in the microsecond just before a high-altitude nuclear explosion of a fission bomb, the component that in turn triggers a hydrogen bomb.

  In the early years of nuclear testing in the atmosphere, the scientists at Los Alamos had no sure way to measure the power of the weapons they had created. One key measurement they sought was the rate of increase of neutrons in a fission bomb, or "neutron flux"—the speed of the chain reaction as the weapon became supercritical. Teller calculated that if the intensity of the fleeting blue light could be captured, it would match the neutron flux. He was right; by measuring the light, it was possible to calculate the yield, the total energy released by a bomb.

  One of the other questions on the index card appeared at first glance to be a general physics question. Its significance became clear only later.

  Standing by at the airport, and well out of view of Gwo-bao Min, was a large group of physicists, nuclear weapons scientists, government lawyers, FBI officials, and classification experts. They were there to examine any documents or notes found in Min's carryon.

  While the airport search was in progress in San Francisco, back at FBI headquarters in Washington, Paul Moore and a smaller group of scientists from the Department of Energy gathered in the office of Edward J. O'Malley, the assistant FBI director for counterintelligence, to hear the result. "If the FBI found the wrong things in his baggage he would be arrested," said Moore.

  The larger contingent at the airport, after examining the index cards, decided there was not enough incriminating evidence to arrest Min. Word was relayed to the group waiting at FBI headquarters.*

  Despite the elaborate deception arranged by the FBI at the San Francisco airport, Min became suspicious of the search of his carryon. Before boarding his plane he tore up the two index cards and gave them to his wife. She went into the ladies' room, followed by a woman who was part of the FBI's Special Surveillance Group, known as the G's.

  The G's are a team of surveillance specialists, all civil servants, but not FBI agents, selected to look like ordinary citizens and blend in to their surroundings. A young mother with a baby in a stroller, college students out jogging, bearded bikers, white-haired grannies toting shopping bags, street repair crews in yellow hardhats, beer-belly good old boys in pickup trucks, young lovers kissing in the park—all may be G's on the job. All are trained in surveillance, photography, and communications.

  Min's wife did not dispose of the pieces of the index cards in the ladies' room. The FBI later recovered the torn pieces from the Mins' trash, in a plastic garbage bag that contained dog poop. A highly dedicated FBI agent reconstructed the cards. *

  Min never reached Hong Kong or China, his original destinations. He flew to Taiwan, turned around, and came home. "When Min arrived back," Paul Moore said, "he went from the gate to the nearest departure gate to see if there were any more 'random' searches at the airport. He had become suspicious; when he looked down the concourse at the departure gate, that was plainly what was going on."

  On the wiretap of Min's telephone, the FBI overheard him say that he had passed information to someone who was supposed to deliver it to an address in Hong Kong but got lost. Min also told Jerry Chen that he had been searched at the airport.

  Now the FBI was faced with a delicate decision. Min had already passed information to Hanson Huang and was trying to answer more questions from Beijing, including about the technique to measure the yield of hydrogen bombs tested in the atmosphere. Could he be allowed to continue working at the lab?

  The bureau decided to leave him in place while the investigation continued. But Min's access to secrets was discreetly reduced. In Washington, the secretary of energy had to sign off, every six months, on approval for Min to remain at Livermore.

  By early 1981 scientists and engineers at the lab, including Min, were already working on what became the Star Wars program to intercept nuclear missiles. Officials decided that leaving Min on the job had become too risky.

  The time had come, Cleveland decided, to confront Gwo-bao Min. Espionage is a peculiar crime. Unless suspects confess or, as rarely happens, are caught in the act,
they may go unpunished. A bank robber may be caught fleeing in a getaway car, an embezzler may be ensnared by an audit. But spies are a different breed, they move in a secret world, often exercising clandestine skills to avoid detection.

  Sometimes a confrontation works. When FBI counterintelligence agents question a suspected spy and reveal how much they know, in some cases even presenting him with surveillance photos, the suspect may feel it is useless to deny the evidence amassed against him. Or the suspect may harbor a hope that his FBI interrogators will offer to turn him into a double agent, working against the other side. At times skilled interviewers, using various ploys, are able to elicit a confession.

  Min was told by lab officials that serious questions had been raised about him by the FBI. As a result, they warned, he could keep his job only if he resolved those issues. He was placed on leave and agreed to talk to the bureau.

  In the first of several days of interviews, Min was asked about the index cards found in his carryon bag and contended that they were just notes he had taken at lectures at the lab. For six hours, he denied knowing Chien Ning or Hanson Huang, then admitted he did but said he knew nothing about any letters from Huang.

  The next day, Min said he had, after all, received a letter from Huang. He agreed to return a third day and produced the show-and-tell innocuous letter. Cleveland asked Min to let the FBI's forensic experts examine the letter, and he consented.

  On the fourth day, Min agreed to take a lie detector test. Cleveland then pulled a rabbit out of his hat and produced a copy of the real, substantive letter that Dan Grove had intercepted with the help of Tommy Tang, the Berkeley student.

  The FBI agents did not want to reveal to Min, however, how they had managed to acquire the letter. They devised a plausible explanation. Chinese characters are frequently written on a pad with preprinted boxes that make it easier to keep the lines straight. Each character, representing a picture of an object or sounds and meaning, fits inside a box. If the substantive letter to Min was written first, as would seem likely, and then ripped off the pad, it might leave an impression on the sheet below on which the for-show letter was written.

  Cleveland told Min that the FBI had retrieved the new letter from the impressions left on the innocuous letter that Min had offered to the agents the day before.

  Min examined the substantive letter closely. Apparently he believed the FBI's invention.

  "I wish to congratulate you," he said. "You have done your job very well."

  Cleveland now thought he had Min on the verge of a confession. But it was not to be. The Livermore engineer said he wanted to talk to his wife before answering further questions. He agreed to meet the FBI agents the next day at a motel, but then telephoned to say he had changed his mind.

  The lab's officials then told Min that since he had not resolved the issues raised by the FBI, he could not remain at Livermore. Min was allowed to resign.

  The tiger had escaped the trap. But the FBI had forced Min out of the nuclear weapons lab and prevented any additional compromise of secrets to China.

  Some who knew Gwo-bao Min argued that he may not have set out to spy for China, but had traveled to Beijing in the hope of making business contacts and once there was pressured to talk about his work at Livermore. And it certainly could have occurred to him that answering the questions he was asked might help him in his efforts to do business with China.

  There was, perhaps, another factor. In Chinese culture, when people receive favors, they are expected to reciprocate, a deeply rooted tradition known as guanxi. Min was treated well in Beijing, as though he was an important and respected visitor. In more than one instance, China has successfully extracted information from visiting American scientists who felt they had to be polite to their hosts and ended up revealing more than they should have.

  But Min seemed to know in advance what would be expected of him in Beijing. There was no other reason for him to have checked out so many classified documents from the Livermore technical library in the weeks before his trip.

  The bureau had maneuvered Min out of the lab, but Cleveland and the FBI continued to pursue the case for a decade more. Now Hanson Huang offered the best hope of a break in the case. In March 1981, one month after Min was forced out at Livermore, Huang flew to New York and then booked a flight back to Hong Kong through Seattle. At the airline counter at JFK, apparently sensing he was being watched, he switched his plans at the last minute to catch his Hong Kong flight in Los Angeles.

  At LAX, the airliner was about to take off with Huang as a passenger when a customs agent boarded the plane and asked Huang to come with him. He was escorted to a hotel where the FBI was waiting. Huang told them little but agreed to meet them again on his next trip to the United States. He met the agents in New York in May and again in August but refused to talk further about his relationship with Min. The Immigration and Naturalization Service then barred him from the country.

  The FBI nevertheless felt it had gathered enough evidence to prosecute Min for espionage. Harry J. Godfrey, Cleveland's supervisor on the TIGER TRAP case, several times pressed John L. Martin, the chief of the Justice Department's internal security section, to move on the case. Martin refused.

  Unless a spy is caught in the act, the FBI cannot make arrests in sensitive national security cases without the approval of the Justice Department. And that meant Martin. Unknown outside the closed world of intelligence, Martin was the man who ruled whether espionage cases would make the front pages and the nightly news or perhaps never become public.

  Without a confession by Min, Martin insisted to both Godfrey and Cleveland, he would not go to a grand jury. In Martin's long career, seventy-six spies had been prosecuted, and all but one convicted. FBI counterintelligence agents were often frustrated by his cautious approach, however, complaining that he was more interested in protecting his reputation than in catching spies. Martin's decision had blocked any legal action against Min, but it did not prevent the bureau from continuing its investigation.

  Late in 1981, Hanson Huang was asked by Chinese officials to brief them on his contacts with the FBI. Then, early in 1982, Huang disappeared from his hotel room in Beijing. A year later he was convicted of espionage against China and sentenced to fifteen years in prison. It was then that PARLOR MAID managed to visit him.

  ***

  With the TIGER TRAP investigation on a hold button, although not closed, counterintelligence officials at FBI headquarters decided to launch a broader probe of whether China was advancing its nuclear weapons program by eliciting information from visiting US scientists. The new case, as an offshoot of TIGER TRAP, was given the code name TIGER SPRINGE. (A rarely used word, "springe" refers to a snare made of a noose under tension that springs when triggered.)

  Dozens of scientists and senior officials in Washington were questioned in the TIGER SPRINGE investigation. Once more, Bill Cleveland and his partner, Al Heiman, conducted many of the interviews. State Department officials, ambassadors to China, and at least two White House national security advisers were questioned, Zbigniew Brzezinski, President Jimmy Carter's National Security Council chief, and Robert McFarlane, who held that post under President Ronald Reagan.

  What the FBI wanted to know from Brzezinski and McFarlane was whether any US scientists or officials had been authorized to share nuclear weapons secrets with China. Both said there had been no such authorization. Cleveland and FBI headquarters officials wanted to be sure that there had been no high-level secret or tacit policy granting permission to share scientific information with Beijing; otherwise, if Gwo-bao Min or other scientists were prosecuted for leaking secrets, they would have a ready-made defense.

  The FBI saw another virtue in TIGER SPRINGE. By casting a wide net, it would demonstrate that the bureau's counterintelligence agents were not interested solely in questioning people who were ethnic Chinese.

  One of those interviewed at length by the FBI was George A. Keyworth, a senior scientist at Los Alamos who later serv
ed as President Reagan's science adviser from 1981 to 1985. On a trip to China in 1980, Keyworth met with Chinese scientists at a university. For years afterward, he was bedeviled by gossip in the intelligence world that he had revealed classified information about the neutron bomb to the Chinese.

  In an interview with the author, Keyworth said that this had never happened. "Someone asked me a question about deuterium and tritium." The question, he said, was related to laser fusion experiments and the neutron bomb, which releases greater radiation than standard nuclear weapons.

  There was no mystery, Keyworth told the Chinese scientists. The isotopes were so unstable that mere impact would ignite them. "I said, anybody who has finished a couple of years of physics knows it is the simplest way to achieve fusion. Put it in a ball and throw it on the floor and it will go off."

  Some officials believed that the Los Alamos physicist had crossed a line, but they were hardly in a position to dismiss or prosecute him for the supposed infraction. "There were good reasons there was no action on Keyworth," said Ken Schiffer, a veteran FBI counterintelligence agent. "He didn't make the trip in a vacuum. It was informal, he was not tasked. But he was made aware of certain gaps in US intelligence, a new facility that China was using in their weapons program and if he could learn anything about that it would be beneficial."

  Before his trip, CIA officials briefed Keyworth on what to look for in China. Robert Vrooman, the CIA's man at Los Alamos, and later chief of counterintelligence at the laboratory, was his principal contact. "I met with other agency people too, but mostly Bob," Keyworth said. "They wanted to know about a lab down near Chengdu. We thought it was a nuclear weapons facility. I was able to validate it."

  More broadly, the intelligence agencies wanted to know the state of China's nuclear weapons program. Ironically, Keyworth got into hot water when, at a CIA debriefing after his trip, he brought up what he had told the Chinese scientists about putting isotopes in a ball, as an example of how adroitly he had handled their questions. "The whole point was when this came up in my debriefing, I was trying to explain how it was possible to circumvent their question by giving a basic answer." Keyworth explained all this to the FBI's satisfaction in several interviews with the bureau during the TIGER SPRINGE investigation.