Enrique Marquez, the friend of San Bernardino shooter Syed Rizwan Farook, was arrested Tuesday in connection with the Dec. 2 terror attack.
The 24-year-old Riverside resident once lived next door to Farook and purchased two of the semi-automatic rifles that Farook and his wife, Tashfeen Malik, used in the massacre that left 14 people dead, federal authorities said Thursday.
According to the Los Angeles Times, Marquez worked as a security guard at a Walmart until recently. Marquez had converted to Islam, prayed at a local mosque, and married a woman from Russia who is related to Farook's older brother.
Marquez purchased the two firearms legally in 2011 and 2012, around the time Farook had originally plotted to carry out an attack. Sources say Farook asked Marquez to buy the weapons on his behalf because he did not want them traced to him, nor did he think he could pass a background check.