Two suspects were arrested in the case, which the district attorney described as an accident between students who were friends.
The district is banning bags at games for the next week and considering the addition of weapons detection devices at event entrances.
More than 200 professionals attended the session, which focused on identifying troubled students and preventing violence.
Three other families, including that of a student who rushed the gunman at the school in suburban Denver, have also filed suit in the wake of their kids’ psychological injuries.
There have been at least 108 incidents of gunfire at school sporting events since 2013, according to a New York Times analysis.
Researchers found that the mental health of kids who survived school shootings, even if they did not experience the event themselves, took a significant dip even three years after the original incident.
Three campuses were reported to have active shooter threats, but police in Newark, Ohio said the calls were faked by two students.
The family of Casey Jordan Marquez, who was killed by a shooter at Aztec High School, says the district ignored security recommendations and did not adequately respond to threats.
The young relatives and classmates of the students killed at Sandy Hook Elementary have begun to claim spots of their own in the school safety movement.
A handwritten note listed more than a dozen students and a handful of school employees in DeSoto, Texas as targets.
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