KVUE-TV screenshot by Chris Matyszczyk/CNET

When is a joke not a joke? When the police say so.

This seems to be the indication in the case of Justin Carter -- 18 years old at the time of the alleged incident -- who has reportedly been sitting in a Texas jail since March.

It all began after a game a "League of Legends." An argument is said to have spilled over to Facebook.

During this argument, Carter was allegedly accused by another gamer of being insane. Gamers say those kinds of things.

Carter's father Jack told KVUE-TV that his son replied: "Oh yeah, I'm real messed up in the head, I'm going to go shoot up a school full of kids and eat their still beating hearts."

A woman in Canada took him seriously. She reportedly found his address and checked to see whether there were any schools in his Austin neighborhood.

When she found that there were, she called the police. It was two months after Sandy Hook.

Jack Carter, however, maintains that his son had added "LOL" and "JK" to explain that his comment had been mere sarcasm.

The police insisted to KVUE-TV that they take all words like this seriously.

But in the meantime, has anyone found any evidence that Justin Carter might be disturbed, might have had access to weapons, might have made such threats before?

This isn't clear at all. However, his father describes him as just a kid who doesn't read the news and doesn't "understand public space."

Justin Carter goes on trial July 1, facing charges of making terroristic threats. He could go to jail for 8 years.

Some might see a parallel between this case and that of Brit Paul Chambers.

Frustrated at the possibility that his flight might be delayed or canceled, he went on Twitter and joked: "Robin Hood airport is closed. You've got a week and a bit to get your s*** together, otherwise I'm blowing the airport sky high!!"

He was, indeed, found guilty. He lost his job and was branded a criminal. It was only the intervention of high-profile sensible people such as Stephen Fry that helped Chambers win an appeal against his conviction.

Carter's friends and family have started a petition at Change.org.

The petition claims there was no actual investigation of Carter's alleged crime. It says he wasn't questioned until a month after he was first arrested. Worse, it says his home wasn't searched until late March and no weapons were found.

If this is true, how seriously were his alleged threats taken? If the police really believed Carter was an imminent danger to others, wouldn't a SWAT team have immediately cordoned off his street, stormed his home, and turned it upside down?

This doesn't seem to have occurred.

It will be interesting to see what evidence might be presented July 1 to justify this apparently draconian action.

It's possible that some new, compelling evidence will be produced by local prosecutors.

Some might suspect, though, that law enforcement might be using this case simply to scare others into not making jokes online about threats of massacre.