SALT LAKE CITY (AP) — A federal appeals court has tossed the conviction of a Utah man who was found guilty of threatening to kill a professor by sending an email containing a violent anti-immigrant poem.

The Denver-based 10th U.S. Circuit Court of Appeals ruled the verdict violated Aaron Michael Heineman’s freedom of speech because it didn’t take into account whether he wanted the professor to feel threatened when he sent the poem in 2011 email that spoke of death with a Bowie knife and noose. Comparing the case to laws criminalizing cross-burning, the panel of judges ruled that anytime speech becomes a crime, courts have to weigh First Amendment rights carefully and say how the crime is different from protected speech.

Heineman told an FBI agent he was just expressing himself and didn’t mean to hurt the professor. His father and his defense attorney argued the then-student at Utah Valley University, who was born deaf and has been diagnosed with Asperger’s syndrome, had a difficult time understanding social behavior and cues.

Prosecutors said the professor called police in fear for the lives of himself and his family when he got the email calling him anti-American and a traitor. They said the poem was one of three emails sent to the professor by Heineman, who also emailed another professor and the Inclusion Center for Community and Justice at Westminster College in Salt Lake City.

Heineman was sentenced to three years’ probation last year, though that was later reduced to two years. U.S. District Judge David Nuffer refused to consider whether Heineman actually wanted the professor to feel threatened, ruling that someone could reasonably be afraid after getting the email.

But in a ruling handed down Monday, the 10th Circuit court tossed the conviction and ordered the Utah court to consider Heineman’s intentions.

A spokeswoman U.S. Attorney’s Office said Tuesday the office is considering its options and there would likely be a new hearing to decide what happens next.

His federal defender, Benjamin McMurray, couldn’t be reached for comment Tuesday.