A 32-year-old Florida man who called himself the "Antifa hunter" was sentenced to federal prison Monday after pleading guilty to making racially motivated threats against an African American politician in Virginia and an autistic Florida girl.

Daniel McMahon, of Brandon received 41 months behind bars on the charges, which included cyberstalking.

“This defendant violated the law by threatening violence against an African-American individual who planned to announce his candidacy for city council and an autistic child merely because the child’s mother opposes his extreme, racially motivated views,” U.S. Attorney Maria Chapa Lopez said at the time of McMahon’s April guilty plea.

The Charlottesville City Council candidate, identified by authorities as “D.G.,” told investigators that McMahon used various social media accounts to threaten him after announcing his intention to run for office.

Accooording to the Associated Press, McMahon called himself “the Antifa hunter,” a reference to anti-fascist, leftist militant activists who confront or resist neo-Nazis and white supremacists at demonstrations.

“The defendant admitted that his posts used racial slurs and invoked long-standing racial stereotypes, and that he intended for D.G. to understand his posts as threats to his safety,” a U.S. Department of Justice news release said.

At his April 30 plea hearing, McMahon admitted he used the accounts to “promote white supremacy and white nationalist ideology, and to express support for racially motivated violence.”

McMahon also admitted he used his “Restore Silent Sam” Facebook account to send intimidating and threatening messages to a Florida activist who had been working to counter white nationalist rallies in her community.

He attempted to use the account to intimidate the woman and tried to extort information about fellow activists by threatening to sexually assault her autistic daughter, investigators said.

“The defendant admitted that, at around the same time that he sent these messages, he also used the internet to conduct searches relating to sexual contact with girls who have autism, the DOJ news release said.

Officials praised the investigation and McMahon’s conviction Monday.

“This defendant weaponized social media to threaten and intimidate his perceived political enemies and propagate a violent white supremacist ideology,” Virginia U.S. Attorney Thomas T. Cullen said. “Because his online activity crossed the boundary between protected First Amendment expression and unlawful threats and harassment, he will spend considerable time in federal prison.”

Once released, McMahon will be placed on three years of supervised release and during that time will be prohibited from using internet-capable devices without court approval.