ATLANTA -- On Thursday, President Donald Trump defended his idea to arm trained teachers and coaches in response to the south Florida school shooting the previous week.

In a viral Tweet, he said that, historically, school shootings last 3 minutes but it takes 5 to 8 minutes to respond.

While that's true in the case of the Parkland shooting, we wanted to see if what he said holds up as a pattern for other school shootings across the country.

Going all the way back to Columbine in 1999, the violence lasted 49 minutes and police were on the scene within 5 minutes.

When gunman Brandon Hill brought a rifle to McNair Middle School here in Georgia in 2013, his standoff with police lasted more than a half hour but police were on the scene within 3 minutes.

The shooting in Sandy Hook lasted 11 minutes and police were on the scene in 2 and a half minutes. While local police departments keep track of their own response times, there's no national database that tracks them. So there's no real way to generalize how long police have to respond to school shootings.

So we verify that tweet as FALSE.

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