A Twitterer calling himself “Kris_Mexicanese” has been having fun testing the limits of the First Amendment. The FBI has been all over him, and I’m sure Homeland Security is watching his every move.

Reason? He joked about the Boston bombing and predicted that it might happen again in Miami.

MIAMI (CBSMiami) – As the Miami Heat wrapped up its second consecutive NBA championship Thursday night, a Twitter account holder posted an ominous message, referencing the Boston Marathon bombing.

“What if what happened in boston at that marathon happened also at the miami heat parade. That’d be Soo cool,” read a post, put up about 11:15 p.m. by a user whose name CBS4 News has chosen not to reveal.

The outrageous posting comes even as the April 15th bombing at the Boston Marathon finish line continues to reverberate through the nation’s psyche.

A little after midnight Friday morning, the same upper and lower case-challenged user tweeted, “boston is gonna occur again so i’ve heard? championship parade monday at 11:00 a.m.” A twisted Twitter joke?

Cops aren’t laughing.

No they are not. Worse, they seem to think that whatever opinions they consider “sinister” ought to be illegal. Not only including insensitive speculation, but criticism of immigration policies. And of course racism.

The tweeter making sinister remarks about Monday’s Heat parade has also posted anti-government tweets. One says “(expletive) immigration!” The reference to immigration enforcement agents comes with a photo of Border Patrol cars at a checkpoint. The user also has posts referencing “hate.” There is racist language used as well.

The FBI issued a statement saying it is “looking at” the Twitter postings. FBI spokesperson, Special Agent Michael Leverock stressing “the importance of reporting suspicious activities” to authorities.

“If you see something, say something,” the statement said, echoing what has become a slogan for homeland security efforts.

There is a clear effort to frighten everyone into following the government line:

“We have detectives in place, we have undercover officers, we are working closely with the FBI, and we will ensure that we have a safe and fun-filled event,” said Miami’s Sgt. Cruz.

Police say those who might be inclined to post threatening or intimidating messages on line need to be aware that, with today’s technology, there is no such thing as Internet anonymity.

Of the tweets in advance of Monday’s Heat parade, one long-time investigator told CBS4 News, “Multiple agencies will be – if they’re not already – crawling all over this guy.”

This is entirely predictable, and I am sure the guy is basking in his 15 minutes of fame. But if you read carefully what he tweeted, it hardly constitutes any kind of threat in the legal sense. Just mere speculation — an expression of a tacky opinion in a semi-literate manner. I don’t doubt that there are all kinds of conspiracy theorists making similar speculations. Speculating that something will happen is hardly a threat, and it is protected by the First Amendment. Just as the vile Fred Phelps is allowed to insult American soldiers who gave their lives for the country, and rooting for lethal hurricanes (anyone remember?) is protected by the First Amendment.

What am I missing? Does the First Amendment no longer apply to opinions that the police might find disturbing?