LANGHORNE, PENNSYLVANIA  (VINnews) – Federal agents searched a storage facility in Langhorne, Pennsylvania, on Monday as part of their investigation into an alleged ISIS-inspired attempt to detonate improvised explosive devices during a protest outside Gracie Mansion, the official residence of New York City Mayor Zohran Mamdani.

The FBI’s New York Joint Terrorism Task Force, working with the NYPD, executed a court-authorized search at the facility in the borough where one of the suspects, Emir Balat, 18, resided with his parents. The search was announced in a Monday night post on X by the FBI’s New York office.

” The FBI New York Joint Terrorism Task Force, along with our partners at the NYPD, will continue pursuing all leads and tips,” the post stated.

Langhorne is located just south of Newtown, Pennsylvania, where authorities searched a home belonging to the parents of the other suspect, Ibrahim Kayumi, 19, on Sunday night.

Balat and Kayumi, both from upscale suburbs in Bucks County near Philadelphia, face federal charges including attempting to provide material support to a foreign terrorist organization and use of a weapon of mass destruction. They were arrested Saturday by NYPD officers shortly after the incident.

Authorities allege the pair plotted to carry out a deadly attack during an anti-Muslim protest outside Mamdani’s Upper East Side residence. Balat allegedly hurled one improvised explosive device toward a crowd and dropped another near police officers. The devices ignited but failed to fully explode, emitting smoke instead of causing injuries or widespread damage.

A federal complaint unsealed Monday revealed the suspects aimed to surpass the death toll of the 2013 Boston Marathon bombing, which killed three people. According to investigators, Balat remarked that the Boston attack resulted in “only three deaths” and expressed intent for something “even bigger.”

After their arrests, both suspects allegedly pledged allegiance to ISIS. Balat reportedly requested pen and paper at an NYPD stationhouse and wrote: “All praise is due to Allah lord of all worlds. I pledge my allegience [sic] to the Islamic State. Die in your rage yu [sic] kuffar.”

NYPD Commissioner Jessica Tisch described “Now die in your rage” as a known ISIS slogan and noted that “kuffar” is Arabic for infidel or non-believer.

“These statements, as set forth in the complaint, made clear that this was not random violence,” Tisch said. “This was a planned attack motivated by extremist ideology and inspired by a violent foreign terrorist organization.”

The Department of Justice described the suspects as ISIS supporters who sought to inflict mass casualties. The investigation remains ongoing, with authorities urging anyone with information to contact tips.fbi.gov or 1-800-CALL-FBI.

Balat and Kayumi appeared in federal court Monday and were ordered held without bail.