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Los Angeles School Police officers watch students lining up to pass through a security check point in the aftermath of two apparent racially motivated student brawls at Thomas Jefferson High School April 21, 2005 in Los Angeles, California.

On January 21, 1993, Demetrius Rice was shot at Fairfax High School when a gun hidden away in a classmate's backpack accidentally fired. The bullet passed through another student before striking 16-year-old Rice, and killing him. 

"It was a boom that you never forget," said David Tokofsky, a former Los Angeles Unified School District teacher and board member who as at Fairfax that day. “The first thought you came to was some joking kid throwing an M-80 firecracker in a trash can. You didn’t think that a gun was in the school.”

That incident led the district to begin performing random weapon screenings using metal detectors. 

Twenty years later. Metal detectors are still in schools. KPCC's Jed Kim reports on whether these tools have made schools any safer.