A Florida man has been sentenced to nearly six years in prison after waging an 18-month cyberstalking campaign against a former schoolmate who wrote an online essay about a traumatic sexual experience with him, according to the U.S. Justice Department.

Byron A. Cardozo, 35, was sentenced in Boston's federal court Wednesday after pleading guilty to one count of cyberstalking and one count of making interstate threats. He was ordered to 70 months in prison followed by three years of supervised release.

A lawyer for Cardozo did not immediately return a request for comment.

Prosecutors say Cardozo began the online harassment in 2017 after a former classmate published an essay describing a 2001 sexual encounter with him. The victim, whose name was withheld to protect her privacy, said it happened when he was 17 and she was 13, when they both attended a school in Florida. She later moved to Massachusetts.

The essay did not identify Cardozo by name, but authorities say he discovered it and sent hundreds of online messages to the woman, including many in the comments section of the essay and on the woman's personal website. Prosecutors say Cardozo threatened to harm the woman and described the encounter in graphic detail, claiming it was consensual.

At times, prosecutors said, he asked for forgiveness and expressed his love for the woman. He continued to harass and threaten her even after she obtained a court order in 2017 forbidding him from contacting her, authorities said.

Cardozo, who previously lived in Jacksonville and Tamarac, Florida, was arrested in 2018 and has been held in custody since then. He pleaded guilty in August.