An improvised explosive device (IED) with the potential to cause "serious injury or death" was detonated and hurled during the Jake Lang-led protests near Gracie Mansion on Saturday, according to New York City officials.
The devices were found near the Upper East Side residence earlier in the day, triggering a major security response involving the New York Police Department (NYPD), federal investigators and bomb-squad units. Authorities later detained several individuals in connection with the incident.
Multiple people briefed on the matter told NBC News that the militant group ISIS was referenced, prompting investigators to examine whether the incident could be linked to the militant group.
Read more: Gracie Mansion protests: 2 in custody after ‘ignited devices’ thrown into crowd
ISIS reference prompts terrorism probe
The two men in custody, Emir Balat and Ibrahim Kayumi, after the devices were ignited, are being questioned by federal agents and the New York Police Department while in federal detention, according to an FBI official.
NBC News reported that the federal and local law enforcement agencies are looking into a possible terrorist plan. According to authorities, one of the suspects mentioned ISIS, the Islamic State group, while being questioned.
{{/usCountry}}NBC News reported that the federal and local law enforcement agencies are looking into a possible terrorist plan. According to authorities, one of the suspects mentioned ISIS, the Islamic State group, while being questioned.
{{/usCountry}}The reference prompted investigators to examine whether the suspects were motivated by extremist ideology or had any connection to known terror networks.
Videos depicted the chaos during the protests, showing a man seemingly shouting "Allahu Akbar," meaning "God is Most Great," at the same moment Emir Balat, the 18-year-old protester from Pennsylvania, reportedly threw an "ignited device."
According to CBS News, a terrorism investigation has been initiated by the FBI's Joint Terrorism Task Force. In Pennsylvania and New Jersey, search warrants were anticipated to be carried out.
Read more: Jake Lang claims he survived ‘assassination attempt’ at Gracie Mansion protests
“Improvised explosive device (IED)”
After the suspects were arrested, the devices were taken to the FBI's Quantico facility for analysis by the NYPD's Bomb Squad.
According to NYPD Commissioner Jessica Tisch, one of the devices was found to be "an improvised explosive device (IED)" rather than a "hoax device or a smoke bomb."
The IEDs were made of triacetone triperoxide, or TATP, a volatile explosive material, per CBS. These explosive materials were filled in glass jars and ringed by broken pieces, like bolts and nuts. An M80-style firework appeared to be linked to the fuse, according to CBS News.
Tisch stated that after hitting a barrier in a crosswalk a few feet away from police officers, Balat's first device went out on its own.
Afterwards, Balat allegedly took a second device from 19-year-old Ibrahim Kayumi, ignited it, and began running with it before dropping it, according to Tisch.