Transcript for Timeline of Terror: Details Emerge About San Bernardino Shooter
And a chilling line coming into focus after the terror arrest linked to the horror in San Bernardino. Enrique Martinez, he and farook had allegededly planned to attack a community college. Now, authorities asking, what did their friends and families know? Here's David Ross. Reporter: The San Bernardino terror plots took shape in a place of American flags, shopping malls and this quiet residential block, where officials tonight say, as in almost every homegrown terror case, someone had to know what was going on. There were individuals in the community, who saw something troubling, who saw someone going towards this path of violent extremism and didn't say anything. Reporter: The timeline to terror began at least eight years ago when Syed farook, then 22, got his then 17-year-old neighbor Enrique Marquez to convert to Islam. Marquez was known to friends as a hapless dupe, a big fan of this punk rock band, interviewed on local TV news after running to rescue a friend's dog. I'm really out of shape. Reporter: Beginning around 2011, farook began to radicalize Marquez, using the videos of recruiter Anwar Al awlaki. We have chosen the path to war. Reporter: In late 2011 and early 2012, farook got Marquez to buy these two assault rifles. And then they hatched their plots to attack the community college they both attended, and open fire on rush hour traffic on the nearby 91 freeway. But they got cold feet and called off the attacks. Still, farook kept planning to kill. And in 2013, he found a new partner in terror. His pakistani-born wife tashfeen. Tonight, authorities continue to look at the statements of those two men, who say they had no idea about a terror plot. Thank you.
This transcript has been automatically generated and may not be 100% accurate.