Senator: San Bernardino Shooter's Neighbor Admitted 2012 Plot

Officials: Enrique Marquez bought “assault-style” rifles used in 2015 shooting.

“He has admitted that he and the deceased were planning to do an attack in 2012, and that they abandoned that because there had been some arrests immediately adjacent to that right in their area, in southern California probably by the counter terrorism people that really caused them to rethink it,” Risch, R-Idaho, told ABC News, echoing comments he made on CNN. “So they abandoned that and did not pursue that event.” Risch, who sits on the Senate Select Committee on Intelligence, said the plan was “very general.”

Farook’s neighbor, 24-year-old Enrique Marquez, has apparently admitted to the FBI some degree of prior knowledge of Farook's plans to carry out violent attacks, McCaul said. Officials said agents will now have to go through the painstaking task of investigating and verifying Marquez’s alleged claims.

Marquez has been questioned by the FBI since late Sunday. Law enforcement officials said they wanted to speak with him sooner, after officials say it was revealed Marquez had purchased the “assault-style” weapons used by Farook and his wife-turned-accomplice Tashfeen Malik, but two days after the attack Marquez checked himself into a mental health facility.

An enigmatic Facebook post by Marquez just hours after last week’s attack indicated he knew something was very wrong. “I’m. Very sorry sguys. It was a pleasure [sic],” he wrote.

In recent days he’s been cooperating with authorities, an official told ABC News. Still, law enforcement officials told ABC News criminal charges are expected to be filed against the young man.

“Just the admissions that he’s made, plus the fact of the weapons that he was responsible for -- originally obtaining these weapons sounds like right around the time they were planning the first attack, that’s sufficient for conviction just with his admissions and the actual steps towards the attack that would be purchasing the weapon,” Risch said.

Marquez’s family has declined to speak about the allegations against him. Law enforcement officials have said the four weapons used in the attack, two “assault-style” rifles bought by Marquez and two handguns purchased by Farook, were all purchased legally in California in late 2011 and early 2012.

CNN first reported the potential 2012 plot, and later The New York Times identified Marquez as Farook’s alleged co-conspirator at the time.