The Justice Department said Marquez and Farook had plotted to carry out attacks in 2011, including throwing pipe bombs on a California highway and targeting Riverside Community College.

Marquez distanced himself from Farook in 2012, U.S. Attorney Eileen Decker said, and Marquez did not have advanced notice of the December 2 shooting in which Farook and his wife killed 14 people.

Marquez was charged with illegally purchasing two assault rifles used by Farook and his wife, Tashfeen Malik. The shooters died hours later in a gunbattle with police. Marquez had no role in the attack, but prosecutors said the guns and bomb-making materials he bought that the couple planned to detonate linked him to the killings.

“While there currently is no evidence that Mr. Marquez participated in the Dec. 2 attack or had advance knowledge of it, his prior purchase of the firearms and ongoing failure to warn authorities about Farook’s intent to commit mass murder had fatal consequences,” U.S. Attorney Eileen Decker said.

Authorities previously said Marquez had legally purchased the high-powered guns.

The FBI investigated the rampage as an act of terrorism and said the Muslim couple were radicalized before they met online and communicated privately about jihad and martyrdom before they married.

President Barack Obama said he was briefed on the investigation Thursday and reiterated the federal government’s commitment to find answers to all the unknowns in the case.

Marquez had deep ties with Farook that extended to a family connection. The two grew up next door to each other in Riverside and then became related through marriage.