Olivia Nuzzi, the star political writer for New York magazine who was placed on leave after she disclosed her personal relationship with Robert F. Kennedy Jr., has accused her former fiancé of a campaign of harassment and blackmail, according to court filings.

In a complaint filed in Superior Court of the District of Columbia, Ms. Nuzzi accused the former fiancé, Ryan Lizza, a top political reporter at Politico, of hacking her devices and stealing a device to surveil her and collect materials to pressure her back into a relationship with him.

She accused Mr. Lizza of bringing “damaging information” to the attention of her employer and of distributing materials to the media that she said she believed to be doctored.

She also claimed in the complaint that Mr. Lizza had threatened her with violence to coerce her into assuming his financial responsibility in a joint book contract, and “explicitly threatened to make public personal information about me to destroy my life, career and reputation — a threat he has since carried out.”

On Tuesday, the court granted Ms. Nuzzi a temporary protection order against Mr. Lizza, which requires him to have no contact with Ms. Nuzzi, and ordered him to “immediately cease using any illegally obtained information.” The protective order was first reported by CNN.

Mr. Lizza said the allegations against him were not true. “I am saddened that my ex-fiancée would resort to making a series of false accusations against me as a way to divert attention from her own personal and professional failings,” he said. “I emphatically deny these allegations, and I will defend myself against them vigorously and successfully.”