An "active shooter" training exercise was conducted Tuesday at South El Monte High School to simulate the response to a report of a shooter on a campus.
The exercise was supervised by personnel from the sheriff's Tactics and Survival Training Unit, and included deputies, school security officers and county firefighters.
Volunteers posed as victims who had been "shot," complete with realistic-looking gunshot wounds provided by makeup artists, and deputies responded to the scene armed with paintball ammunition modified for use with a service weapon.
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"The deputies are going to come in and deal with an active shooter scenario -- that's all they know," an official told KNX Newsradio. "They know that they received a call for service at this high school that said 'there's someone shooting on this campus,' and when they get in, they're going to deal with the multiple threats: possibly multiple shooters, possibly an (explosive device)."
The drill comes about a week after a shooting at an elementary school in San Bernardino left a teacher, a student and the gunman dead.