Enrique Marquez, friend of San Bernardino shooter Syed Rizwan Farook, is likely to be charged for buying Farook rifles in 2012. The rifles were purchased for the abandoned 2012 plot, and were used in the December 2 attack that killed 14 people.
The charges against Enrique Marquez are expected to partly be based on allegations that Marquez had bought two rifles that Farook and Farook's wife used in the December 2 mass shooting and terror attack that left 14 people dead in the Southern California city.
Details about when the charges would be filed weren't immediately available.
Marquez, 24, has told investigators he didn't know about the plans for the San Bernardino attack, U.S. officials have said.
But he has acknowledged that he bought the two AR-15s for Farook several years ago, and he told investigators about a 2012 attack plot that he says he and Farook conceived but did not carry out, U.S. officials told CNN.
Marquez is a convert to Islam and was very close friends with Farook.
Farook's wife, Tashfeen Malik, who was also killed alongside her husband in a police shootout following the attack, pledged allegiance to ISIS leader Abu Bakr al-Badghadi during the shooting.