Keller nodded. Then he explained that Seymour, in the late 1980s, was dissatisfied with the level of intelligence he was receiving from MI5’s informants in Northern Ireland. He wanted to insert his own agent into the IRA badlands of West Belfast to report on the movements and associations of known IRA commanders and volunteers. It was not a job for an ordinary MI5 officer. The agent would have to know how to handle himself in a world where one false step, one wrong glance, could get a man killed. Keller met with Seymour at a safe house in London and agreed to take on the assignment. Two months later he was back in Belfast posing as a Catholic named Michael Connelly. He took a two-room flat in the Divis Tower apartment complex on the Falls Road. His neighbor was a member of the IRA’s West Belfast Brigade. The British Army maintained an observation post on the roof and used the top two floors as barracks and office space. When the Troubles were at their worst, the soldiers came and went by helicopter. “It was madness,” said Keller, shaking his head slowly. “Absolute madness.”

While much of West Belfast was unemployed and on the dole, Keller soon found work as a deliveryman for a laundry service on the Falls Road. The job allowed him to move freely through the neighborhoods and enclaves of West Belfast without suspicion and gave him access to the homes and laundry of known IRA members. It was a remarkable achievement, but no accident. The laundry was owned and operated by British intelligence.

“It was one of our most closely held operations,” said Keller. “Even the prime minister wasn’t aware of it. We had a small fleet of vans, listening equipment, and a lab in the back. We tested every piece of laundry we could get our hands on for traces of explosives. And if we got a positive hit, we put the owner and his house under surveillance.”

Gradually, Keller began forming friendships with members of the dysfunctional community around him. His IRA neighbor invited him for dinner, and once, in an IRA bar on the Falls Road, a recruiter made a not-so-subtle pass at him, which Keller politely deflected. He attended mass regularly at St. Paul’s Church—as part of his training he had learned the rituals and doctrines of Catholicism—and on a wet Sunday in Lent he met a beautiful young girl there named Elizabeth Conlin. Her father was Ronnie Conlin, an IRA field commander for Ballymurphy.

“A serious player,” said Gabriel.

“As serious as it gets.”

“You decided to pursue the relationship.”

“I didn’t have much choice in the matter.”

“You were in love with her.”

Keller nodded slowly.

“How did you see her?”