One of two men accused of throwing improvised explosive devices at protesters Saturday outside the New York City mayor’s residence appears to have purchased fuses at a fireworks store in a Philadelphia suburb last week, CBS News has learned.  

Emir Balat, 18, purchased fuses at Phantom Fireworks,in Penndel, Pennsylvania, according to William Weimer, vice president and general counsel for the Phantom Fireworks Company.  

Surveillance video provided to CBS News shows Balat walking inside and shopping at Phantom Fireworks at 12:46 p.m. local time on March 2, five days before the incident.  

Video from inside the store shows Balat purchasing a 20-foot roll of safety fuse, which looks and feels like thick twine, for $6.89 including tax, according to Weimer.

“Coming in and buying that was uneventful,” Weimer told CBS News in a phone interview. “Had he bought 20 rolls of fuse, it might have raised eyebrows. But buying one or two items of anything in this store is almost a nonevent. Nothing remarkable about the purchase.”

The FBI, which is investigating the attack as an act of potential terrorism, contacted the store’s national security director on Monday, Weimer said.

Balat and 19-year-old Ibrahim Kayumi, both residents of Bucks County, Pennsylvania, are accused of driving to New York City Saturday, where they took part in a counter-protest against an anti-Islam demonstration organized by far-right influencer Jake Lang near Gracie Mansion, the official residence of New York City Mayor Zohran Mamdani. 

Videos from the scene, verified by the CBS News Confirmed team, show a man identified as Balat throwing what authorities described as an “ignited device.”

Prosecutors alleged in a complaint that Balat said he was inspired by ISIS and told police he wanted the attack to be “even bigger” than the Boston Marathon bombing that killed three people in 2013.

According to New York Police Commissioner Jessica Tisch, the first device thrown by Balat extinguished itself after striking a barrier in a crosswalk, a few feet from police officers.

Balat then ran away and retrieved a second device from Kayumi, lit the device and started running with it before dropping the device, Tisch said.

Law enforcement sources told CBS News that the devices consisted of a sports-drink bottle filled or partially filled with explosive material set inside glass jars and surrounded by fragmentation, or nuts and bolts. 

Kayumi is not seen in the March 2 surveillance video at Phantom Fireworks.

The FBI did not immediately respond to a request for comment from CBS News.

Balat’s attorney, Mehdi Essmidi, did not immediately respond to a request for comment, but outside Balat and Kayumi’s initial federal court appearance Monday in New York City, he indicated he planned to fight the charges against his client.

Balat and Kayumi were charged with five counts related to terrorism and possession of explosive materials. A federal indictment is forthcoming.  

Kayumi’s attorney also did not respond to CBS News’ requests for comment.