(JNS.org) The St. Louis man accused of being behind some of this year’s bomb threats against American Jewish institutions plead guilty Tuesday to cyberstalking charges, saying he threatened the institutions to disrupt his ex-girlfriend’s life and cause her “great distress.”

“For this, I deeply apologize,” said Juan Thompson, 32, The Associated Press reported. Thompson faces up to five years in prison for each charge against him.

“Thompson made these threats as part of a cruel campaign to cyberstalk a victim with whom he previously had a relationship,” said Acting U.S. Attorney for the Southern District of New York Joon H. Kim. “Thompson’s threats not only inflicted emotional distress on his victim but also harmed Jewish communities around the country.”

Thompson was arrested by the FBI March 3 for as many as eight bomb threats to more than a dozen Jewish institutions, include one targeting the Anti-Defamation League’s New York headquarters. Authorities collected evidence from his home, including about two-dozen laptops, tablets and cell phones.

More than 150 bomb threats were made against Jewish institutions during the first few months of this year. A few weeks after Thompson’s arrest, Israeli authorities arrested an 18-year-old Israeli-American man believed to be behind the majority of the threats.