The FBI has released images of a weapons stockpile authorities say a 21-year-old Pennsylvania man was assembling for an ISIS-inspired mass shooting before agents moved in and arrested him. Jonathan Kramer, of Valencia, allegedly purchased a semi-automatic rifle and nearly 200 rounds of ammunition, along with knives, a scope and other gear federal investigators seized during the operation near Pittsburgh. Prosecutors say Kramer had pledged allegiance to ISIS online and discussed carrying out attacks using firearms, explosives, drones and even ricin, describing the plot as a mission to wage war against non-Muslims. Agents tracked his movements before he could allegedly act, arresting him outside a hotel where he had checked in with the weapons.

The case adds to a growing list of ISIS-inspired plots federal authorities say they have disrupted across the country in recent months, underscoring the bureau's continued focus on lone-actor extremist threats. Kramer had reportedly been on investigators' radar since a prior juvenile case years earlier, and authorities say renewed concerning behavior after his release prompted the fresh investigation that led to his arrest. He is now facing federal charges tied to receiving firearms and ammunition in connection with terrorism, and prosecutors have asked that he be held without bond. Officials say the newly released images are meant to show the public just how close the alleged plot came to being carried out.