A man identified as Alexander Heifler was arrested after authorities say he planned to firebomb the home of activist Nerdeen Kiswani.

The plot was uncovered through a weekslong undercover operation by the New York City Police Department, which infiltrated communications and monitored the suspect’s activities.

Investigators say Heifler assembled Molotov cocktails and conducted surveillance of the target’s residence before being apprehended.

He has been charged with making and possessing destructive devices and appeared in federal court following his arrest, the AP has reported.

Officials described the case as an example of law enforcement intervening to prevent a politically motivated violent attack.