Two Ohio girls stand accused of saying vile, menacing things on Twitter — seriously accused. The high schoolers, ages 15 and 16, were arrested and face a possible six months in juvenile detention. They are charged with threatening a 16-year-old rape victim in the celebrated case involving Steubenville High School football stars. Two boys were convicted of the rape this week.

But what about these two girls? Were they being mean, reckless and stupid, or were they making a serious threat requiring police intervention? Ohio Attorney General Mike DeWine said that whether a threat is made on the Internet or in person, it has to be taken seriously. Given the passions surrounding this case, the concern seems warranted.

That said, it’s hard to deal with people, especially young people, sharing their antisocial intentions on social media — things they don’t necessarily plan to act on. Many regard the Internet as a place for unloading angry fantasies. It’s a safe place precisely because anything goes.

Nowadays, nearly every place in America finds itself coping with troubling online conversations. In Rhode Island, for example, the Warwick school superintendent wants to discipline students for tweeting profane language about the state school commissioner. (They objected to her forcing high schoolers to pass a difficult math exam.)

The local affiliate of the American Civil Liberties Union said these students were acting immaturely, but that posting obscene messages off school property was protected free speech. Verbal behavior deemed impermissible on school grounds takes on a different nature in cyberspace, so the ACLU seemed to argue.

The Steubenville rape case unfolded on social media from start to finish. The crime was recorded and publicized on Twitter posts and videos shared by others at the scene, a wild teenage party held late last August. There, a drunk or drugged 17-year-old girl was dragged around and repeatedly raped by football team members. Like many of the other partygoers, the boys also may have been far from sober.

High school football is a source of happiness in this struggling steel town. Many residents railed against ruining the future of these promising young men, especially when the victim herself was reportedly stumbling drunk.

After the verdict, the 16-year-old arrested for threatening the girl posted a message on Twitter saying, “You ripped my family apart, you made my cousin cry.” It had an almost innocent teenage air until she added that when they met, “it’s gone be a homicide.”

The lawyer for the younger girl said her client had been targeted for going online to support one of the accused players. She sent out her offensive posts after having received hundreds of harassing phone calls, some from abroad.

So how do we isolate criminal behavior in the babbling chaos? People offer brutal scenarios online that they would never put down on paper.

In the recent “Cannibal Cop” case, a New York City jury had to distinguish between a sick imagination and plans to a commit a monstrous act. A city police officer had been scheming — in his head or for real — to kill women and eat them. His lawyers argued that he’d been accused of a thought crime, that he was engaging in a kind of sophisticated online game. After combing through his bizarre Internet searches and some ambiguous actions, the jury decided to hand down a guilty verdict.

The online intimidation in Steubenville certainly could not be ignored as a harmless adolescent rant. But the nature of the online free-for-all makes the girls’ real intentions hard to interpret. We’re operating in a foggy legal and cultural world, and there’s no way out.

Froma Harrop is a Providence Journal columnist. Her email address is fharrop@projo.com