How to keep kids safe in schools is a question that’s top of mind for the entire U.S. following last week’s deadly mass shooting at an elementary school in Uvalde, Texas.

In Miami-Dade County in Florida, part of the school district’s strategy is posting an armed police officer in every school from the beginning of the day to the last bell. The district is the fourth largest in the country and its police force is the largest, with a budget of $65 million.

As a district with hundreds of thousands of students, Miami-Dade Schools Police Chief Edwin Lopez said they deal with a “large amount of threats,” sometimes partnering with the Secret Service or FBI to investigate them.

Lopez said threats often have no specific timing, forcing detectives to, “come in and start working these cases in order to ensure that school the next day starts in a safe manner.”

The officers operate out of a headquarters located about an hour from Marjory Stoneman Douglas High School, where a 2018 mass shooting left 17 dead.

From the central command center, law enforcement can see 18,000 live cameras installed at every school in the county. They even have technology to alert them to the sounds of gunshots in the area.

Such alerts could be vital during active shooter incidents, Lopez says, when time is of the essence and minutes make all the difference.

“Our officers train on a single officer response during these casualty incidents; that’s critical. There’s no delay in our response,” Lopez said.

While there are national recommendations for school safety, there are no federal standards. But Lopez said there is a requirement for him and his team should there be an active shooter at one of their schools.

“If there is an individual that’s coming to our schools to hurt innocent kids, our officers are specifically trained to neutralize the threat, and in other words to kill the person that is trying to hurt our children,” Lopez said.

The chief added that while they unfortunately can’t guarantee anything, they have added layers of safety to schools that give the Miami-Dade district an advantage in preventing such an unthinkable tragedy.