Yet Chino’s turn to militant Islam was neither swift nor decisive. He felt conflicted about his criminal livelihood but unwilling to start over. His solution, his brothers said, was to give his money away. He dispensed with watches. He regaled his Moroccan nieces with gold necklaces and rings. One day, while traveling in Holland, he called his brothers and told them to set fire to his cars. “Life is worth nothing,” Chino told his brother Mustafa. “We won’t live long.” (They ignored the instruction. “Mustafa likes cars,” one brother explained.)

Chino had come to believe that Muslims who earn money illegally suffer in the afterlife — unless they put the money to good use. He began sending cash to the mother of the man he had stabbed in Tetouan. He continued to drink and do drugs. But his drunken binges sometimes ended with him crying over the stabbing and the mother of the victim, one of his Madrid friends, Abdelilah el Fadwal el Akil, recalled. “He would say that it was his fault she had lost a son, and that the least he could do was take care of her,” Akil wrote to me from a Spanish prison, where he was being held as a defendant in the Madrid bombing trial.

During a rare visit home to Morocco in 2000, Chino was arrested for the man’s murder and imprisoned in Tetouan. But key evidence was still missing in the case, including a witness who failed to appear. Chino’s parents hired a local criminal attorney, Mourad Elkharraz, who told them their son stood a good chance of acquittal. The lawyer assured them that the process would take no more than a year. Instead, it dragged on for three. During that time, the lawyer witnessed a startling transformation in his client. At first, the change was merely physical. Chino went from wearing gold necklaces and jeans to a gray, Afghan-style tunic and matching pants. He began carrying a Koran. Then he started fasting on Mondays and Thursdays. He stopped swearing and began peppering his sentences with “Allah.” Eventually he became a prison imam, leading prayers five times a day. “He said: ‘I’ve become someone else. I’m a new man,’ ” the lawyer told me. “But his anger rose more and more.”

Chino grew deeply frustrated by the delays in his case. He yearned to see his son, an absence that “broke his heart,” Chino’s mother said. He lost his temper in meetings with his lawyer, demanding to know why his case had not been resolved. Yet every time Chino got angry, his lawyer recalled, something odd happened: he turned to the subject of Palestine. He seemed to conflate the personal with the political. In one breath, he would say that “Jews mistreat Muslims”; in another, that he wanted to “do jihad” to the Moroccan judges who kept him in prison. By then, Chino had befriended another prisoner who belonged to a banned Islamist party, Justice and Charity. Chino took a brief interest in the group, but he concluded it was “too passive,” according to documents filed in the Madrid bombing case.

Chino was finally freed from the Moroccan prison in June 2003; the court declared him innocent of the murder charge, Elkharraz, his lawyer, said. But Chino returned to Spain a different man. He had become obsessed with the war in Iraq, his brothers recalled. He said he couldn’t sleep at night knowing that women and children were dying at the hands of Americans, all in the greedy pursuit of oil. He no longer had time for small talk. He would walk into a room and within minutes begin the same diatribe.

“He would say, ‘The soldiers of bin Laden are soldiers of God,’ ” Chino’s brother Jaber told me. “Because the world was looking for them —”

“And couldn’t find them,” said another brother, finishing the sentence.

Chino told his brothers to cut their hair, to stop smoking, to stop going out with girls. He scolded them for not praying and urged a sister in Holland to wear a veil. He seemed agitated that so many of his siblings — eight in all — had moved to Europe and began pressing them to return to Morocco. “This isn’t paradise,” he would tell them. They soon tired of his campaign. He had become unbearably serious. He told his childhood friend Anwar that if he wanted to continue the friendship, “you have to go to the mosque.”