Officials have arrested a former Northeastern University employee in connection with a bomb scare at a virtual reality lab on campus last month, NPR reports. Authorities say the employee filed a false claim when reporting the alleged incident.

On Sept. 13, Boston Police and FBI bomb squads responded to calls that a suspicious package had exploded in one of the labs on Northeastern campus. Jason Duhaime, then-director of the university’s Immersive Media Lab, had made the 911 call, NPR reports.

Duhaime told authorities he had opened a plastic case that had been mailed to the lab and was injured by flying debris when the case then exploded. He also claimed to have found a letter criticizing Facebook founder Mark Zuckerburg and condemning virtual reality developers. But investigators have no said there were no signs of an explosion, and that they discovered a copy of the letter on Duhaime’s computer, per NPR. 

“Throughout the course of the investigation, we believe [Duhaime] repeatedly lied to us about what happened inside the lab, faked his injuries, and wrote a rambling letter directed at the lab threatening more violence,” Joseph Bonavolanta, the FBI special agent overseeing the case, said Tuesday, per CNN.

Duhaime is no longer employed by Northeastern, per a Tuesday statement from the university.