According to the September bulletin distributed to law enforcement around the country and obtained by CNN, no specific credible threat exists surrounding the Pope's visit, but gatherings planned in New York, Philadelphia, and Washington that have been designated "National Special Security Events," which require a massive amount of coordination and planning by multiple law enforcement agencies.
The preparations come amid a new ABC News report of a 15-year-old boy who was arrested for allegedly plotting
an ISIS-inspired attack on the Pope when he visits Philadelphia.
The assessment highlights some of the recent terror-related arrests of alleged homegrown violent extremists in the United States and expresses concerns over these potential lone wolf attackers "because of the difficulty in discovering such individuals or independent groups until they are operational."
The pope's visit is also deemed to be "a powerful motivator for groups or individuals with anti-Catholic or anti-Christian viewpoints" who may justify violence for religious reasons, citing recent attacks carried out by al Qaeda or ISIS inspired groups such as Boko Haram in Nigeria or al-Shabaab in Kenya.
Federal law enforcement estimates some events, such as the open-air Sunday Mass in Philadelphia, will attract crowds of well over a million people, making it a challenging environment to secure. But in an effort to identify potential threats, a number of behavioral indicators were listed that could be deemed "pre-operational surveillance" or "attack planning," including "suspicious purchases of dual-use items that could be used to construct an explosive device, unusual or prolonged interest in motorcade movement dynamics and security, and discreet use of cameras or video recorders, sketching, or note-taking."
Though the intelligence provided in the bulletin is "absent a specific, actionable threat," the information was circulated in a collaborative attempt to "aid law enforcement and first responders in identifying and mitigating threats."
The papal visit also presents unique challenges because Pope Francis doesn't want security so heavy it prevents his interaction with pilgrims, and because of perceived threats from potential attackers not on the radar of law enforcement.
Addressing members of the Commonwealth Club of California in San Francisco on Tuesday, Homeland Security Secretary Jeh Johnson noted the difficulty of thwarting lone-wolf homegrown terrorists inspired by what they read on the Internet. He cited the Boston Marathon bombing and Chatanooga, Tennessee, attack, among others, as evidence of the phenomenon.
"It is, for the most part, smaller scale attacks, but, in many respects, harder to detect, because it involves the so-called lone wolf who could strike with little or no notice in the homeland," Johnson said.