I asked him what he thought of that title. He shrugged. “What people don’t understand is that sewers don’t generate the crap, they clean the city, they take the crap away,” he began. “Rome triumphed because it had good sewers.” He told me about a sanctuary in the Roman Forum, the Shrine of Venus Cloacina, built to celebrate the city’s drainage system. “Sure, you go into certain places and you come out smelling bad. But someone has to do this work, and instead of punishing the guy who does this job, we should think about thanking him.”

The spy began recounting to me the long story of his life. He was born in 1951 in the Andalusian town El Carpio, a son of a pharmacist and a midwife. Villarejo started his career in Franco’s military during a time when conscription was mandatory. If the morality of fighting for a dictator weighed on him as a young man, it certainly didn’t show now. He reminisced about Antonio González Pacheco, known as Billy the Kid, a notorious police agent of the regime who later was charged with torture. (“He was a great success,” Villarejo said.) He joked about a failed coup d’état in 1981, attempted by right-wing officers who burst into the Congress of Deputies with guns. Villarejo was flipping through the decades like someone trying to find his place in an old book.

I interjected to ask about his time as a soldier — why did he leave the military? Villarejo took a deep breath. He was a loyal soldier, he said, but the army was just not for him. “Since I was always rebellious, I could have been an anarchist. But another side of me believed in order, discipline and the fatherland. I wanted to help my country, but I couldn’t submit to the rules.”

Unhappy as a soldier, Villarejo instead became an intelligence agent. In the early 1970s, he joined the Social Investigation Brigade, a branch of Franco’s secret police charged with rooting out disloyalty. Most often, the targets were leftist activists and student leaders who were jailed for years. Political opponents were silenced with blackmail, fed by secrets delivered up from tapped phone lines.

Villarejo was at the center of these dark arts, and he seemed to relish describing them to me in detail. He recalled a somewhat cinematic incident from his undercover work against ETA, involving a woman he met at a bar in the seaside city San Sebastián. One morning, while leaving her bedroom, Villarejo said he ran into Iñaki Pérez Beotegi, who went by the alias Wilson, a leader of the very group he had been pursuing. “At that moment, we both knew we were with the same woman,” Villarejo recalled, saying the men didn’t exchange words. The love triangle continued — “it was the ’70s,” he told me, as though this explained everything you needed to know — and Villarejo began to press the woman for intelligence on her other boyfriend. While this sort of 007-style intrigue was impossible to confirm decades later, what was clear was that Villarejo seemed to live for it.