Social media posts can provide a valuable insight into someone's state of mind, but from a legal perspective, deciphering the exact nature of that insight can still be a bit like looking at a Rorschach test. The answer can change depending on who you ask.

Late last year, journalist Ernest Owens was brought in for questioning by the Philadelphia Police Department's counterterrorism unit after someone complained about a comment he posted on Facebook. Owens had been responding to a post chastising patrons of a nightclub called “iCandy” whose owner made headlines back in 2016 for using a racial slur.

“I say … they will be shown better than told. I will just leave it at that. A great reckoning is coming,” his comment read.

Owens told The Philadelphia Inquirer that the police overreacted and should not have interrogated him over a Facebook post. He alleged that his civil rights had been violated, but the department was exonerated following an internal affairs investigation.

Lisa Mathewson, a criminal defense lawyer practicing in Philadelphia, said that were a similar case ever to go to court, the onus would fall on the jury to decide whether or not the person posting such a statement had knowledge that his or her communication would be perceived by a reasonable person as threatening.

“Ultimately it may not get to a jury, but then your question is, who the decision-maker? Is it just the police officer's perception? Is it the complainant's perception? And how to we make sure that the decision-makers who intervene short of it getting to the jury are giving adequate room for First Amendment protected speech?” Mathewson said.

She added, “So much of criminal law, particularly in the white-collar arena, turns on mental state. What did the person intend, what did the person know, when did they know it? And only rarely do you have direct evidence of that. But the things that people say are some of the best types of evidence of what's in their mind.”

Further complicating matters is the hyperbolic nature of mediums like Facebook or Twitter, where it can be difficult to tell whether an inflammatory post will be translated into an action that threatens public safety, or if someone has just made the mistake of tweeting while angry.

In the instance of the Philadelphia case, Mathewson cited circumstances, like the post's proximity to the date of the Mummers Parade (an annual New Years Day celebration featuring brightly colored costumes and music) that may have influenced the police's decision to bring Owens in for an interrogation.

“The individual reporter who was questioned was flabbergasted that his commentary might have been perceived as a threat, but given the fact that there was a parade scheduled, that there was this public safety factor, the perception of the individual who notified the police is something that clearly the police took seriously,” Mathewson said.

She thinks that the vast majority of social media-related cases will be solved at the investigative stage, after law enforcement officers have assessed the seriousness of a potential threat and determined whether there's cause for further action. If the subject of one of these investigations did feel that their civil rights had been violated based on the content of a social media post, they would have to prove that the police were engaging in viewpoint discrimination or stifling protected speech.

Law enforcement's interaction with social media doesn't end with threats. In September, the U.S. Securities and Exchange Commission sued Tesla CEO Elon Musk for securities fraud shortly after he tweeted that he was considering taking the company private and had the funding to do so secured. The SEC called Musk's statements “false and misleading.”

“What folks forget is that statements can be actions and statements alone. They can move markets, they can make policy if it's a public official making the statement and the fact that the statement is made on social media doesn't change the way that law enforcement is going to see it,” Mathewson said.