Law enforcement officials and relatives identified the gunman in Sunday's mass shooting at an Orlando gay nightclub as Omar Mateen, a 29-year-old from Fort Pierce, Fla. (Myspace)

In many ways, Omar Mateen fits the stereotype of an American mass shooter. Mateen, who had a seemingly troubled family background, had significant problems with romantic relationships and seemed to have been frustrated in his career. When he chose to lash out, he targeted a place that he knew would be full of people. He was able to legally purchase the weapons to carry out the attack, despite having raised a few red flags a couple of years earlier.

Yet Mateen's brutal assault on a popular gay nightclub in Orlando — which killed at least 49 people, the deadliest mass shooting in U.S. history — is not being viewed in the same way as recent mass shootings by Dylann RoofJames Holmes or Adam Lanza. Instead, the shooting has quickly been placed deep inside a broader conversation about radicalization and the threat posed by the Islamic State militant group.

Why exactly? To many, the answer no doubt seems obvious. In a 911 call from the club during the attack, Mateen himself told a dispatcher that he was a follower of the Islamic State. Then, after the attack Sunday, a news agency linked to the group, Amaq, released a statement that cited a "source" as saying that Mateen was an "Islamic State fighter." Finally, Islamic State radio on Monday called him "one of the soldiers of the caliphate in America."

These three strands of evidence were enough for many to link the attack on the nightclub to the Islamic State, with presumptive Republican presidential nominee Donald Trump quickly taking to Twitter to blame "radical Islamic terrorism" and to reassert his support for a ban on Muslim arrivals to the United States. (Mateen was a U.S. citizen born in New York.)

Analysts, though, noted that there is a distinction between attacks directed by the Islamic State and those inspired by it — and it's a distinction the group likes to blur. "People are so ready to give the Islamic State as much credit as possible, as it's easier to compute," said Charlie Winter, a terrorism analyst at Georgia State University. "The organization is getting exactly what it wants whenever it wants."

At this early stage, it remains unclear whether there is a deeper link between Mateen and the Islamic State, but officials say they have seen no signs of a direct connection. This is a key point.

For example, the deadly attacks this year in Brussels were perpetrated by a network of individuals with serious ties to the Islamic State; in some cases, members of that network had traveled to the group's strongholds in Syria and Iraq and back to Europe. The Islamic State appeared to be crucially involved in the planning and execution of that attack.

On the other end of the scale, when Syed Rizwan Farook and Tashfeen Malik fatally shot 14 people at the Inland Regional Center in San Bernardino, Calif., in December, it was later revealed that the couple had made a pledge of allegiance to the leader of the Islamic State, Abu Bakr al-Baghdadi, in a post on Facebook. But investigations have found no evidence that the Islamic State played a direct role in planning or perpetrating the attack: The couple appeared to have been inspired by the idea of the Islamic State, if nothing else.

Despite that, the Islamic State issued statements appearing to assert responsibility for both of the attacks. But there was a difference. Rita Katz, director of the SITE Intelligence Group, notes that after the Brussels attacks, the Islamic State "released communiques in half a dozen languages as well as audio messages and more" that claimed responsibility. There was nowhere near such an expression of support for the San Bernardino couple.

Katz says the Islamic State's response to the Orlando attack seems more similar to the San Bernardino response. Others agree. Aymenn Jawad al-Tamimi, a research fellow at the Middle East Forum who follows Islamic State media closely, says Amaq's use of the word "sources" may imply that it was testing the waters with its claim, but he also suggests that from the Islamic State's perspective, it was immaterial whether the organization had a direct role in the attack. "Any person who can carry out an attack in the West having pledged allegiance to the Islamic State is perfectly legitimate in the Islamic State's eyes," Tamimi says.

In the past, the Islamic State has issued claims for attacks that later appeared to be contradicted by other reports. Winter suggests that "media strategists of the Islamic State" may wait and watch for the emerging "news media narrative" before deciding how to exploit it. "A lot of thought has gone into how best to structure this form of branding mechanism," he says. The situation in Orlando appears to follow this pattern.

"ISIS found out about [Mateen's] pledge through the news media and embraced him as one of its own," Katz says, using an acronym for the Islamic State.

In statements, Islamic State spokesman Abu Muhammad al-Adnani has appeared to court those who may be willing to stage an attack in the West on their own, telling potential recruits that “the smallest action you do in their heartland is better and more enduring to us than what you would if you were with us.” The Islamic State was not necessarily the first extremist group to try to influence disgruntled Western citizens and residents — Winter notes that al-Qaeda in the Arabian Peninsula also has tried something similar. But the Islamic State's strategy appears to have been more successful.

Such a strategy may appeal to religious extremists. It may also appeal to a troubled person intent on creating mass mayhem. The Orlando attack blurs the lines between terrorism and the United States' mass-shooting problem, setting off debates not only about radicalism but also about hate crimes and gun control in an especially polarized election year. As some analysts have noted, buying a gun in the United States can be far easier than creating a bomb — which generally requires some expertise.

The result of the strategy is simple: It makes the Islamic State look more powerful. But it also has a bigger effect — sowing the seeds of discord and division in the West.

Here's what you need to know about the guns some are calling "the gold standard for mass murder," after Orlando shooter Omar Mateen used the assault-style rifle Sig Sauer MCX to kill at least 49 people. (Editor's note: This video has been updated with more specific information.) (Gillian Brockell/The Washington Post)

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