NEW YORK — The attempted attack on a provocative cartoon contest in Texas appears to reflect a scenario that has long troubled national security officials: a do-it-yourself terrorism plot, inspired by the Islamic State group and facilitated through the ease of social media.
Trying to gauge which individuals in the United States pose such threats — and how vigorously they should be monitored — is a daunting challenge for counterterrorism agencies. Some experts caution that a limited number of small-scale attacks are likely to continue.
Michael McCaul, chairman of the House Homeland Security Committee, said federal authorities are aware of “thousands” of potential terrorists living in the U.S., only a small portion of whom are under active surveillance.
Concerns have been intensifying since the rise of Islamic State terrorists and were heightened this week after two gunmen were shot dead while trying to attack the event in Garland, Texas, that featured cartoon images of the prophet Muhammad.
One of the men, Elton Simpson, 31, of Phoenix, was arrested in 2010 after being the focus of a four-year terrorism investigation. Investigators are trying to determine the extent of any terrorism-related ties involving him or his accomplice, Nadir Soofi.
At the White House, Press Secretary Josh Earnest said Wednesday that intelligence officials would investigate the Islamic State’s claim of responsibility for the incident.
“This is consistent with what has previously been described as a lone wolf attack,” Earnest said. “Essentially you have two individuals that don’t appear to be part of a broader conspiracy, and identifying those individuals and keeping tabs on them is difficult work.”
Terrorism experts say the spread of social media — and savvy use of it by terrorist groups — has facilitated a new wave of relatively small-scale plots that are potentially easy to carry out and harder for law enforcement to anticipate.
While plots orchestrated by al-Qaeda historically have involved grand plans designed to yield mass carnage — airline bombings, for instance, or attacks on transportation systems — the Islamic State terrorists have endorsed less ambitious efforts that its leaders say can have the same terrorizing effect on Western society.
“If you can get your hands on a weapon, how is the state security apparatus supposed to find you?” said Will McCants, a fellow for the Center for Middle East Policy at the Brookings Institution in Washington, D.C.
This phenomenon poses a challenge for investigators as they sift through countless online communications.
“It’s exceptionally difficult to estimate of the number of people who’ve considered becoming foreign fighters,” said William Braniff, executive director of a terrorism research center at the University of Maryland.
