DENVER (KDVR) — A man convicted and sentenced for stalking a Colorado singer is now saying his messages were protected under the First Amendment in a case that’s before the U.S. Supreme Court.

In 2017, Billy Raymond Counterman was sentenced to four and a half years in prison for stalking Colorado singer Coles Whalen. Whalen’s attorney says the messages started escalating in 2014.

“I think best estimates is that she received more than a thousand unwanted communications from Counterman,” said Paul Cassell, an attorney representing Whalen. “Coles received hundreds of communications, and many of those were threatening. They were references to her needing to die and references to the fact that Counterman was following her or following friends of hers, and so those communications caused her to need to leave her home and ultimately to give up her career as a stage performer.”

But now, Counterman is appealing a lower court’s decision by arguing his messages were protected by free speech. The Supreme Court decided to take up his appeal, with oral arguments starting Wednesday.

Are the messages considered ‘true threats’?

“It’s not surprising in the sense that the standard has long been unclear as to what constitutes what they call a ‘true threat,'” said Ian Farrell, a law professor with the University of Denver.

The Supreme Court is now tasked with deciding whether Courtman’s messages are considered true threats, which are statements not protected by the First Amendment.

“Colorado’s law says it is a true threat and therefore can be criminalized and punished if an objectively reasonable person would believe that there was actually a threat on their safety,” Farrell said.

However, Counterman cites mental illness and argues he didn’t intend to hurt Whalen.

“The standard being argued by the defendant is that in order for it to go outside of protection of the First Amendment and be punishable, the government must prove that the speaker intended for the victim to be put in fear of their life or physical safety,” Farrell said.

The Supreme Court is expected to rule by the end of June.