San Bernardino jihadis' friend spoke of "sleeper cells" before attack

“He would say stuff like: ‘There’s so much going on. There’s so many sleeper cells, so many people just waiting. When it happens, it’s going to be big. Watch,’ ” said Nick Rodriguez, a frequent patron who had known Mr. Marquez on and off for the past two years. “We took it as a joke. When you look at the kid and talk to him, no one would take him seriously about that.”…

Mr. Marquez’s cooperation with investigators could turn out to be very detrimental to his future. His purchase of the assault rifles for Mr. Farook and his planning of an attack in 2012, if proved, would be federal crimes that come with stiff sentences, according to law enforcement officials. While the authorities say they are grateful for his cooperation, they will almost certainly charge him, officials said.

Mr. Marquez has not yet been charged with any crime, and he has told investigators he did not know that the couple were plotting the shootings at the Inland Regional Center in San Bernardino. But Mr. Marquez’s role is particularly concerning because counterterrorism officials believe that he represents a strand of impressionable people at life’s margins with no obvious connections or sympathies with terrorist groups, who can be goaded or enticed toward violence.