Federal prosecutors filed criminal charges Thursday against the longtime friend and former neighbor of one of the San Bernardino shooters.
The first criminal charges stemming from the mass shooting were brought against Enrique Marquez, friend and former neighbor of attacker Syed Rizwan Farook, according to the Department of Justice.
Marquez appeared in court Thursday afternoon and, in a brief six-minute appearance told the judge he understood the charges against him.
Marquez has been charged with three criminal counts, including conspiring with Farook in 2011 and 2012 to commit terrorism, illegally purchasing the two assault rifles used in the Dec. 2 attack and violating immigration law by entering into a sham marriage with one of Farook's family members, according to the Department of Justice.
There is no evidence Marquez participated in the Dec. 2 attack.
Investigators have said Marquez bought the two assault rifles three years ago that wound up being used in the Dec. 2 shooting at a health center in San Bernardino. Marquez told the FBI that he bought the weapons as a favor so Farook, who worked with many of the victims, would not have to go through a background check or be on record as the buyer, officials told NBC News.
According to prosecutors, Farook and Marquez met in 2005 when Marquez moved to Riverside. Farook introduced Marquez to Islam and Marquez converted in 2007. The pair spent time reviewing radical Islamic materials, including "Inspire," the publication of Al-Qaeda in the Arabian Peninsula.
Marquez told investigators that the pair discussed making plans in late 2011 to carry out acts of terror, including a plot to attack the library or cafeteria at Riverside Community College, where they had both been students.
The pair also discussed a possible attack on the 91 Freeway at rush hour.
The friends bought firearms, ammunition, explosives materials and other items needed to carry out the attack, but in 2012 Marquez began to distance himself from Farook and ceased plotting.
There was no response Thursday morning from family members at the home where Marquez lives with his parents. Law enforcement agents raided the home a few days after the mass shooting.
The American-born Farook, 28, and wife Tashfeen Malik, 29, shot and killed 14 people attending a holiday party at the Inland Regional Center. They were killed hours later in a shootout with law enforcement agents.
Federal authorities have said the pair had self-radicalized in the years before the mass shooting.
Investigators also were exploring whether Farook and Marquez discussed plans to launch some type of attack several years ago. They became apprehensive because of unrelated arrests in the area, NBC News reported.
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, which investigators now say was a sham marriage for immigration purposes.
On Wednesday, FBI Director James Comey said there is no evidence that the couple posted publicly on social media about their commitment to jihad before Malik arrived in the United States in 2014 on a K-1, or fiancee visa. The clarification was intended to address confusion over whether the husband and wife posted extremist messages publicly that could have been detected when Malik applied for a visa before coming to the United States.
All of Malik's statement in support of jihad were part of private messages or emails, Comey added. Those private social media posts were not discovered by authorities until after the mass shooting.
There also is no indication that the couple had direct contact with terror organizations, Comey said.
On Friday, President Barack Obama plans to meet with the victims' families. The meeting in Southern California was added to Obama's long-scheduled trip to Hawaii for Christmas vacation.
Marquez will be back in court Monday when a judge may consider bail.