The San Bernardino terrorist attack at the Inland Regional Center in California killed 14 and injured 20. The attack was carried out by Tashfeen Malik and husband Syed Farook who were both killed in a shootout with police hours after the Dec. 2 attack. The ISIS-linked attack was later discovered to also involve a neighbor and friend of Farook. Today authorities have arrested said neighbor who has been charged with terrorism. 

A law enforcement official told ABC News 24-year-old former neighbor to Farook, Enrique Marquez, has been been arrested and charged with "conspiring to provide material support to terrorists," per the Department of Justice.  

According to investigators, Marquez purchased two assault style rifles used in the San Bernardino attacks back in late 2011 or early 2012. Authorities think Farook asked Marquez to buy them. 

Marquez hinted at his involvement in a cryptic Facebook status hours after the San Bernardino attack writing, "I'm. Very sorry sguys [sic]. It was a pleasure."

Marquez has reportedly been cooperating with the FBI, providing information. A counter terrorism official told ABC News, "He's continued to cooperate with investigators since they got ahold of him."