Law enforcement and school officials at Chester Academy were actually preparing for a hostile event drill on Tuesday, when a 911 call came in and turned a drill into reality.

Chester Union Free School District Superintendent Sean Michel says a large law enforcement presence was on scene in minutes. Undersheriff Anthony Weed says that's exactly the plan when a critical incident call comes in.

Days after the incident, Orange County District Attorney David Hoovler issued new suggestions he recommends for districts to follow to ensure everyone is communicating effectively, that evidence is preserved and that districts follow up on mental health-related issues.

"[We're] working together on a regular basis doing this training, getting as much information as they can and keeping that open line of communication so that if they do have a threat, they need to bring the DA's office in as soon as possible," Weed said.

The DA said in a release that these suggested procedures will hopefully bring schools and law enforcement closer together to ensure the safety and protection of students, and will ensure that justice can be served after the incident.