All four Florida residents had their guns taken away by judges under a "red flag" law the state passed three weeks after authorities say a mentally disturbed man killed 17 people in a shooting at Marjory Stoneman Douglas High School in Parkland two years ago Friday.

The law, supported by legislators of both parties , has been applied more than 3,500 times since, with the pace accelerating during the last half of 2019. Even so, an Associated Press analysis of the law showed its use is inconsistent, with some counties and cities using it rarely and others not at all.

Advocates of Florida's red flag measure say before it existed, it was often difficult to remove firearms from those making threats or suffering severe mental breakdowns. Investigators did not act on reports that the Parkland shooter was threatening to carry out a school massacre. But even if they had, it is likely he would have been allowed to keep his guns because he had no felony convictions or involuntary, long-term mental commitments, they say.