(REUTERS) — A former U.S. journalist pleaded not guilty on Monday to making bomb threats against Jewish organizations in the United States while posing as his ex-girlfriend in retaliation for her breaking up with him.

Juan Thompson, 32, entered his plea at a brief hearing before U.S. District Judge Kevin Castel in Manhattan. He is charged with one count of cyberstalking, according to a court document.

Federal prosecutors have said Thompson engaged in a vicious, months-long harassment campaign against his ex-girlfriend, using various email accounts to accuse her of possessing child pornography, driving drunk and, finally, making bomb threats targeting Jewish groups.

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