The White House said Wednesday that the shooting in Texas for which the Islamic State has claimed responsibility was consistent with a lone-wolf attack, while a terrorism watch group said the violence may have been inspired by an al-Shabab extremist from Minnesota who is wanted by the FBI.
While cautioning that U.S. intelligence officials are still evaluating the Islamic State’s claim, White House press secretary Josh Earnest said the attack by two gunmen in Garland, Texas, appears to have involved “two individuals that don’t appear to be part of a broader conspiracy.”
“Based on what we know now, and there’s still a lot more that we have to learn, this is consistent with what has previously been described as a lone-wolf attack,” Mr. Earnest said.
But a group that monitors extremists said the two gunmen who were killed in the Texas shootout may have been inspired by an al-Shabab militant from Minneapolis who called for the violence. The Counter Extremism Project, which is headed by former Homeland Security adviser Frances Townsend, said extremist Mohamed Abdullahi Hassan called on his “brothers” to attack the “Draw the Prophet” contest in Texas and compared it with the killings in France this year at the satirical magazine Charlie Hebdo.
“The brothers from the Charlie Hebdo attack did their part,” Hassan tweeted April 23, 10 days before the Texas attack. “It’s time for brothers in the #US to do their part.” He included a link to the “Draw the Prophet” contest in Texas where the shootings occurred.
The 25-year-old Minnesotan, also known as Mujahid Miski, left Minneapolis in 2008 to join al-Shabab in Somalia and was indicted in 2009 on terrorism-related charges.
The Islamic State group also praised the men who died while trying to attack the contest in Garland on Sunday and claims to have “trained soldiers” in 15 states.
“Out of the 71 trained soldiers, 23 have signed up for missions like Sunday, we are increasing in number. … Of the 15 states, 5 we will name … Virginia, Maryland, Illinois, California and Michigan,” an American terrorist known as Abu Ibrahim Al Ameriki said on a file-sharing website. The authenticity of the claims could not be verified.
Rep. Michael T. McCaul, chairman of the House Homeland Security Committee, said federal authorities are aware of thousands of potential extremists living in the U.S., only a small portion of whom are under active surveillance.
A senior Pentagon official, who spoke on the condition of anonymity, said Wednesday that the department has not issued a directive to beef up security at various bases and that officials do not believe the latest threat by the Islamic extremist group “is anything more than words.”
“Surely ISIL’s propaganda and their tweeting and their radio stations and their website and their magazine — all these things have the ability to attract lone-wolf-type activities,” the official said. “But we, at the Department of Defense, do not see any legitimate ISIL linkages in the United States.”
Police departments in the D.C. region were not taking extra precautions on account of the purported claim, authorities said.
“There’s no specific change in our normal security measures,” said U.S. Park Police spokesman Lt. Allan Griffith. “Just the normal state of diligence.”
Terrorism analysts say the spread of social media — and savvy use of it by extremist groups — has facilitated a wave of relatively small-scale plots that are potentially easy to carry out and harder for law enforcement to anticipate.
“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. “It’s attractive because it gets just as much attention as a small to midsize bomb.”
A public forum like Twitter, with its millions of users, means those who otherwise might have had limited exposure to terrorist ideologies now have ample access to what FBI Director James Comey has described as the “siren song” of the Islamic State group. Social media provides a venue for agitators to exhort one another to action, recruit followers for violence and scout locations for potential attacks.
“The speed with which someone can find an active jihadist and connect with them over Twitter, let’s say, and start direct messaging with them — that speed happens much faster now,” Mr. McCants said.
This phenomenon poses a challenge for investigators as they sift through countless online communications.
“Where is the threshold of saying this is more than just an avid consumer of propaganda?” asked William Braniff, executive director of a terrorism research center at the University of Maryland and a former instructor at the U.S. Military Academy’s Combating Terrorism Center.
U.S. intelligence officials are investigating the Islamic State’s claim of responsibility. Analysts are reviewing whether the claim is accurate and, if so, at what level the group knew about or possibly sanctioned the attempted attack.
“There’s a lot to review here, and that work has not yet been completed,” Mr. Earnest said.
Such an attack “is the kind of thing that would be very difficult to deter and prevent,” he said.
About 20 minutes before the attempted attack in Texas on Sunday, a final tweet posted on an account linked to one of the gunmen said: “May Allah accept us as mujahideen,” or holy warriors.
Among the hashtags used by the account was “#texasattack.”
Federal authorities confirm that the Twitter account belonged to 31-year-old Elton Simpson, a Phoenix man who opened fire along with another gunman, said Mr. McCaul. The Texas Republican was briefed on the investigation by federal law enforcement officials.
Mr. McCaul said the Twitter account linked to Simpson included images of Anwar al-Awlaki, an American-born radical cleric killed in a CIA drone strike in Yemen. But the lawmaker stopped short of saying law enforcement missed a red flag.
“Was he on the radar? Sure he was,” Mr. McCaul said from Turkey, where he was leading a congressional delegation. “The FBI has got a pretty good program to monitor public social media.”
The Department of Homeland Security and the FBI issued a joint intelligence bulletin to local law enforcement April 20 warning that the Garland event was a possible target for a terrorist attack, according to a Homeland Security official who was not authorized to be quoted discussing the document.
Social media accounts linked to “violent extremists” had been focusing on the contest, the bulletin said. According to mainstream Islamic tradition, any physical depiction of the Prophet Muhammad — even a respectful one — is considered blasphemous.
U.S. Park Police, which has jurisdiction over the National Mall, will step up security during Memorial Day weekend festivities that draw crowds to national monuments. Police would take the same action for any event on the Mall that draws a significant crowd, Lt. Griffith said.
The purported Islamic State threat posted online Tuesday circulated on social media similarly to another vague threat that emerged in March, naming 55 cities and small towns as potential targets.
Lexington Park, Maryland, was among the nine Maryland and Virginia towns named in the March threat. The St. Mary’s County sheriff took extra security precautions as a result.
Despite contacting federal authorities about the matter, the sheriff “never received anything official” verifying the authenticity of the online threats, said Sgt. Cara Grumbles.
“The only thing we ever saw was through social media and the news reports. So the sheriff and command staff looked at that and took some steps,” she said, declining to specify what measures were taken.
⦁ Maggie Ybarra contributed to this article, which is based in part on wire service reports.