The U.S. Supreme Court will revisit the case about a Pennsylvania man arrested for a series of threats and rap lyrics he wrote online about his ex-wife, co-workers and police, according to Slate.com.

The case tests free speech in an Internet context, but the briefing before the trial has become "a master class on rap music for aging jurists," Slate.com reported.

Anthony Elonis began to post dark, violent rap-style lyrics on Facebook after his wife left him and took his kids, according to Slate.com. He was sentenced to almost four years in prison, which he has already served.

Some of his posts included rap-style lyrics about shooting up kindergarten classes, hurting his former wife and killing the FBI agent investigating his posts, Slate.com reported.

According to organizations including the American Civil Liberties Union, it is not necessarily what he said but the fact that he was never judged to have a "subjective intent to threaten" someone else, according to Slate.com.

Due to this definition, civil liberties groups argue his online posts should not be considered a "true threat" under the law, Slate.com reported. They also argue he should be protected by the First Amendment's right to free speech.

The issue of someone's intention is even more important when it comes to online threats, where remarks can be "abbreviated, idiosyncratic, decontextualized, and ambiguous," according to Slate.com.

"[S]peakers should not face prison time based solely on misjudgments about the scope of their audience or how a potentially unintended recipient would react to a message," the groups argued in their brief, Slate.com reported.

A similar case in Utah ruled this week that because a white supremacists did not intend for the recipient of his remarks to feel threatened, his conviction was not valid, according to Slate.com. The three-judge panel of the 10th Circuit Court of Appeals ruling may lead the way for Elonis' case.