A Staten Island man was arrested for stalking after waging a decades-long campaign of harassment against a woman who was once his fourth-grade pen pal, authorities said.

Jason Christopher Hughes, 46, allegedly wrote a stream of creepy e-mails to two women — one of whom he had been writing letters to since the 1970s, according to court documents. In the e-mails, Hughes wrote about “darkness” and “evil” he would bring to the woman.

He and his former pen pal met in the late ’70s when they became pen pals and Hughes sent “hundreds” of letters that described his troubled home life, court papers said.

When the woman stopped responding, he allegedly turned up at her college dorm and later threatened to kill her and her loved ones.

Hughes wrote in the e-mails that he “hates” children and laughs when they are “eaten by wild dogs.”

He also sent the woman a link to a Smithsonian magazine article about five children who died in a fire.

Hughes also allegedly sent a second woman disturbing e-mails about dismembering bodies, according to the documents.