Police in Volusia County, Florida, recently arrested a 15-year-old boy who joked about carrying out a mass shooting on a video game chat platform. "Joke or not, these types of comments are felonies under the law," the Volusia County Sheriff's Office said on Facebook. "After the mass violence we've seen in Florida and across the country, law enforcement officers have a responsibility to investigate and charge those who choose to make these types of threatening statements."

According to the sheriff's office, the boy, who attends Seabreeze High School in Daytona Beach, posted this message, using a pseudonym: "I Dalton Barnhart vow to bring my fathers m15 to school and kill 7 people at a minimum." The teenager was charged under a statute that says "any person who makes, posts, or transmits a threat in a writing or other record, including an electronic record, to conduct a mass shooting or an act of terrorism, in any manner that would allow another person to view the threat, commits a felony of the second degree." A second-degree felony is punishable by up to 15 years in prison.

In a video that the sheriff's office posted on Facebook, one deputy handcuffs the teenager outside his home while another explains to the boy's mother that "he's under arrest currently for making a threat to cause a mass shooting [or] act of terrorism." The mother is incredulous and becomes increasingly upset when it becomes clear that her son is being taken to a juvenile detention facility, where he will remain for at least a few days.

"He's just a little kid playing a video game," she says.

"All these kids keep getting arrested," the deputy says. "That's why the FBI and the local law enforcement are spending so much time, because how do we know he's not going to be the kid from Parkland, he's not going to be the next kid, the kid that shot up Sandy Hook? We don't know that. So when you draw the attention to you by making statements…They may be jokes. I mean, I wouldn't expect a kid to say, 'I'm dead serious. I'm going to fucking go shoot everybody up.' No, when they're caught, it's a joke. 'I didn't mean it. It's a joke.' That's when you're caught."

The boy's mother tries to put his comment in context. In "these games, these kids say stuff like that all the time," she says. "It is a joke to them. It's a game. And it's so wrong. I hate that game."

The deputy concedes that teenagers commonly joke about mass shootings. But at the same time, he says, you never know. "Guess what my time in law enforcement is spent doing," he says. "It's arresting kids for making these statements all the time and for stopping acts too….That's what our job is, is to make contact, because these kids think it's a game or a joke, so they go ahead and make these comments."

The mother still can't believe that a joke can be a felony. "He's a little boy," she says. "He didn't do anything wrong. Yes, he's a teenager, but he's still a little boy. He's not one of the crazy people out there doing stuff….He shouldn't be treated as though he's a terrorist or something because he made a silly statement on a stupid video game….You have to look at these things case by case….I mean, he's not that person."

The deputy asks her if she owns a gun, and she says she does. "He has hands and feet," he says. "He can grab your gun and go do something."

When the mother says "he would never do anything like that," the deputy insists that "we don't know." He complains that "this is the world we live in, where people think it's funny to say, 'I'm going to go kill people at school.'"

Notice that the deputy offers three rationales for hauling this kid away in handcuffs. First, he might actually be planning a mass shooting. Second, even if he was kidding, such jokes force police to waste resources by investigating teenagers who do not have any actual plans to kill people. Third, people should not joke about mass shootings, and Florida's legislators have decided to make that a crime.

It makes sense for police to investigate when someone reports that a student has threatened to shoot up his school. But if it turns out that the kid was joking, does his statement still qualify as a "threat"? In this case, it seems that the police are not trying to prevent a mass shooting so much as punish a teenager for saying the sort of stupid, tasteless things that teenagers tend to say. The fact that the sheriff's office posted the video as a warning to others suggests that the authorities want everyone to know that jokes about mass shootings are not only offensive but felonious.

It seems doubtful that the boy's joke, in context, would qualify as a "true threat," a category of speech that the Supreme Court has said is not protected by the First Amendment. UCLA law professor Eugene Volokh, a First Amendment specialist, says it's problematic to assert, as the sheriff's office did, that it does not matter legally whether the boy was joking.

"The sheriff's office quote seems not quite right, because the statute requires 'a threat,' and obvious jokes aren't treated as threats," Volokh writes in an email. "To be a 'threat,' something at least has to come across as a serious threat—and not just a joke—to a reasonable observer. Some courts also say that the speaker must have specifically intended that people feel threatened, or at least know that this would be the likely reaction. Other courts, however, think it's enough that a reasonable observer would find it threatening, which makes it a sort of negligence-based crime….It may well be that this statement would have indeed been reasonably viewed as a genuine threat, whatever the 15-year-old's intention might have been."