RIVERSIDE, Calif. — The man who bought the assault rifles his friend used in the San Bernardino massacre was charged Thursday with a terrorism-related charge alleging he plotted earlier attacks at a college and on a congested freeway.

The duo, who had become adherents to radicalized Islam ideology as neighbors in Riverside, plotted in 2011 and 2012 to maximize carnage by using pipe bombs and guns to kill innocent people at a campus cafeteria and those stuck in rush hour traffic, court documents said. The plots fizzled.

Enrique Marquez Jr., 24, was charged with conspiring to provide material support to terrorists for those earlier plots with Syed Rizwan Farook.

Those plans may never have come to light if not for the Dec. 2 terrorist attack where Farook and his wife, Tashfeen Malik, used guns Marquez bought years ago to kill 14 people at a holiday meeting of Farook’s health department co-workers.

Marquez was charged with illegally purchasing the rifles that the shooters used again hours later in a gunbattle with police. The couple were killed in the shootout.

In his initial court appearance, Marquez showed no emotion as he gave one-word answers to the judge.