LOS ANGELES—A San Fernando Valley man was sentenced Friday to 15 months in federal prison for sending a series of threatening emails to the FBI, including threats to bomb the bureau’s Westwood office and references to the notorious Unabomber.

Mark William Anten, 53, of Sun Valley was convicted in June of two federal counts of threats by interstate communication, according to the U.S. Attorney’s Office.

Evidence presented at a three-day trial in downtown Los Angeles showed that from July 2023 to December 2023, Anten sent a series of increasingly threatening communications to the FBI, culminating in two threats to bomb the FBI field office in Westwood. Even after being warned by authorities, Anten double-downed on threats to murder FBI employees, court papers show.

Federal prosecutors said that on Nov. 2, 2023, Anten emailed FBI agents saying he was voted most likely in his graduating class to become the next Unabomber—a reference to Ted Kaczynski, whose 20-year bombing campaign killed three people and injured nearly two dozen more. Kaczynski was convicted of federal crimes, spent the bulk of his prison sentence in the SuperMax federal prison in Colorado and died in prison in June 2023.

In the Nov. 2 email, Anten listed similarities between himself and Kaczynski, proclaimed that he was working on a manifesto, and signed his email “Unabomber,” according to prosecutors.

On Nov. 20, 2023, two FBI agents interviewed Anten in front of his home. During the interview, Anten admitted to sending the previous communications and the officers admonished him to stop contacting agents, evidence showed.

Despite the admonition, Anten’s conduct escalated. On Dec. 5, 2023, Anten sent a string of threatening emails to FBI agents, in which he threatened to “Unabomb” the FBI’s Los Angeles office, according to the evidence. In one email sent on Dec. 6, Anten emailed agents, “I can go on a mass murder spree. In fact, it would be very explainable by your actions” and signed it, “SuperMax or Death.”

Prosecutors said he also sent an email that included an image depicting the results of a Google internet search for “how to make a dirty bomb.”

Later on Dec. 6, 2023, Anten visited the FBI’s Westwood office and emailed agents that he had visited their building and would continue to do so, prosecutors said. Surveillance footage confirmed Anten’s presence there.