SAN BERNARDINO, Calif. (KABC) -- Monday marked four years since the terror attack in San Bernardino rocked the nation, leaving 14 people dead and 22 others wounded Several events are honoring those killed and injured in the senseless tragedy.A moment of silence will be held at 10 a.m., and a memorial is planned for 3 p.m. at Cal State San Bernardino.Syed Farook and his wife Tashfeen Malik used semi-automatic rifles to gun down more than a dozen people at a Christmas party for San Bernardino County employees on Dec. 2, 2015, prosecutors say. Police later confronted and killed the two attackers.Enrique Marquez - a former neighbor and friend of Farook - allegedly bought the two rifles for Farook in 2011 and 2012, and the two planned to launch bomb and shooting attacks at Riverside City College , where they attended classes, and a notoriously gridlocked section of highway without exits. The two never carried out those plans.Marquez is facing up to 25 years in prison.