The friend and former neighbor of San Bernardino attacker Syed Rizwan Farook was arrested and charged with conspiring.  He is accused of plotting attacks on a college and freeway. E nrique Marquez, 24, is accused of conspiring with Farook to provide material support to terrorism in 2011 and 2012, making a false statement in connection with the acquisition of firearms, and immigration fraud, according to a statement from the U.S. Department of Justice.

The immigration fraud charge is connected to Marquez’s “sham marriage” to Farook’s sister-in-law’s sister — Mariya Chernykh, who is Russian. They married on Nov. 29, 2014, the complaint states.  He is believed by authorities to have bought two assault rifles used by Farook and Farook’s wife, Tashfeen Malik, in the Dec. 2 mass shooting and terror attack that left 14 people dead in the Inland Empire city.

While he has not been charge with involvement in the San Bernardino attack, Marquez bought the AR-15-style rifles used in the shooting, as well as explosive material used to construct a pipe bomb that was found at the attack site. A complaint also accuses Marquez of planning terrorist attacks with Farook in 2011 and 2012 that were not carried out, the Justice Department said.

Marquez reportedly told investigators he and Farook had planned to attack the library or cafeteria at Riverside Community College. They also, allegedly, had plotted to attack State Route 91 during rush hour. Marquez told investigators that the plan was to throw pipe pipe bombs on the freeway, and then to open fire on stopped vehicles, the Justice Department said.

Neither attack took place. After 2012, Marquez purportedly stopped planning with Farook and distanced himself from his friend after the arrests of Ralph Deleon and others on terrorism-related charges.

Since the San Bernardino shootings, Marquez has waived his Miranda rights, cooperated with investigators and provided information, officials have said. He also checked himself into a mental health facility.  According to the complaint, Marquez called 911 on December 3 and told the operator that Farook was behind the San Bernardino attack and had used his gun in the attacks

Authorities are still trying to learn more about whom the killers interacted with, how they hatched and carried out the plot and why.