About the same time a couple opened fire at the Inland Regional Center in San Bernardino in December, Barbara Holmes' son, who suffers from autism, was on his way there.
As she watched the news unfold on a department store TV, unsure if he had arrived and unable to contact him, she felt helpless.
Holmes eventually learned that her son was safe, having been diverted from the center before arriving. But she's haunted by the powerlessness that overcame her that day.
She was one of dozens to attend an active shooter training hosted last weekend by the San Bernardino County Sheriff's Department to teach the public what to do if confronted by a mass shooter.