Who was Omar Mateen?; Is Orlando the US’ Paris attack?; ISIS’ south Syrian progress; Conflict simmers on Africa’s east coast; and a bit more.

Who was Omar Mateen, and how did this man on a U.S. law enforcement watchlist slip through the system? Investigators are racing to find out as much as they can about the now-dead 29-year-old New York-born man variously described as bipolar, abusive, and not terribly religious or social who killed 50 people and wounded another 53 Sunday morning in Orlando during the worst mass-shooting in America’s history—and the deadliest terrorist attack on U.S. soil since Sept. 11, 2001.

“Law enforcement authorities said that Mr. Mateen, wielding an assault rifle and a pistol, stormed the club and called 911 from inside to declare his allegiance to the Islamic State, the brutal group that has taken over parts of Syria, Iraq and Libya,” The New York Times reports. “Mr. Mateen had been investigated in the past for possible terrorist ties, but the F.B.I. ultimately found no evidence. Still, he was believed to be on at least one watch list.”

How he met his end: “A three-hour standoff followed the initial assault, with people inside effectively held hostage until around 5 a.m., when law enforcement officials led by a SWAT team raided the club, using an armored vehicle and explosives designed to disorient and distract. Over a dozen police officers and sheriff’s deputies engaged in a shootout with Mr. Mateen, leaving him dead and an officer wounded, his life saved by a Kevlar helmet that deflected a bullet.”

About those previous looks into Mateen by U.S. authorities: “The F.B.I. investigated Mr. Mateen in 2013 when he made comments to co-workers suggesting he had terrorist ties, and again the next year, for possible connections to Moner Mohammad Abusalha, an American who became a suicide bomber in Syria, said Ronald Hopper, an assistant agent in charge of the bureau’s Tampa Division. But each time, the F.B.I. found no solid evidence that Mr. Mateen had any real connection to terrorism or had broken any laws.”

Despite his pledge to ISIS, authorities are focusing more on what appears to be Mateen’s “self-radicalization” than any actual training and preparation by the terrorist group. Indeed, the Islamic State’s chief spokesman put out a call for followers to attack the U.S. during Ramadan, as CNN reports.

But the bigger picture view suggests, as the Times’ Rukmini Callimachi writes, that to ISIS, whether Mateen was acting for the group or was motivated by his own hatred toward gays, makes little difference. “Influencing distant attackers to pledge allegiance to the Islamic State and then carry out mass murder has become a core part of the group’s propaganda over the past two years. It is a purposeful blurring of the line between operations that are planned and carried out by the terror group’s core fighters and those carried out by its sympathizers.” More on that psychological glimpse into the exporting of terror, here.

And as Defense One’s Tech Editor Patrick Tucker wrote in the wake of the Chattanooga shooting not yet a year ago, even with a list of eight warning signs to look out for in the next “lone-wolf” attack, it remains incredibly hard to stop these episodes of mass violence. Find the eight behaviors from the psychological literature here.

Worth noting: the attack in Orlando “comes at a time of catastrophic military losses” for ISIS in Iraq and Syria, said Patrick Skinner of the Soufan Group.

Indeed, the U.S.-led coalition has killed “more than 120 Islamic State leaders, commanders, propagandists, recruiters and other so-called high-value individuals so far this year,” LA Times’ Bill Hennigan reported this weekend. A bit more on the ISIS battles in Iraq and Syria below.

Across the pond, the war goes on… With Orlando on everyone’s mind, Defense Secretary Ash Carter, his entourage and the Pentagon press corps departed Monday morning for NATO headquarters in Brussels—and the final gathering of defense ministers before next month’s presidential-level summit in Warsaw. Defense One’s Executive Editor Kevin Baron is along for the ride. The meeting was billed as expected, he writes: counter-ISIS, Russia, Afghanistan. But for certain the attack in Orlando gives a bit more focus to what European security officials already have learned: terrorism in their homelands.

Just two months ago, European and British security officials spoke plainly at the Aspen Security Forum in London about how they are evolving their counterterrorism thinking—and policymaking—past battlefield wins and borders control. Instead of just trying to stop terrorism, there’s an urgent sense of wanting to stop citizens and others within their populations from ever becoming terrorists to begin with. That’s a step the U.S. has not reached, not as robustly, at least, in part because Americans had not yet had their Paris, their Brussels, their Istanbul. Now they have. Now they have Orlando.

NATO defense ministers usually use their final pre-summit meeting to lockdown future commitments to the Afghanistan war, their budget shortfalls, and other pledges. Will they connect their collective security mission to Orlando? Or will we see any “official” as-NATO participation in the war against ISIS. It’s a long way from Belgium to Florida. Today, it feels a little bit closer.


From Defense One

Welcome to the Monday edition of The D Brief, by Ben Watson, Bradley Peniston, and Kevin Baron. On this day in 1917, 162 Londoners die in the largest German air raid of World War I. Send your friends this link: http://get.defenseone.com/d-brief/. And let us know your news: the-d-brief@defenseone.com.


ISIS is losing big in northern Syria, but growing at a concerning clip in the south, Middle East scholar Hassan Hassan warns. And this is a “remarkable development,” he writes, because “the Southern Front has been hailed as a good example of international support to the opposition.”

What you should know: “Last month, three local groups in Deraa formed Jaysh Khaled bin Al Walid. ISIL announced the merger on Friday. The groups—namely the Yarmouk Martyrs Brigade (YMB), Islamic Muthanna Movement (IMM) and Mujahideen Group—operate mainly in western Deraa. Last Thursday, the US state department designated the YMB as a terrorist group. For ISIL, the south in general is strategically and symbolically important. Deraa borders Israel and Jordan and has historical resonance. The new formation is named after the historical Muslim figure, Khaled bin Al Walid, who commanded a key battle in the Yarmouk Basin against the Byzantine empire in the 7th century.”

Moving forward, “The loyalty of three groups in the Yarmouk Basin to ISIL presents more than a military challenge,” he writes. “Their members are combat ready and locally entrenched in a strategic area in which ISIL long desired to build influence. These groups are still outnumbered and can be defeated, but the story of how ISIL could establish presence despite persistent setbacks sheds light on its long game.” Read the rest, here.

In Iraq, Baghdad says it’s using investigations and arrests to salvage the deeply-fraught Fallujah offensive just days after reports emerged Sunnis escaping the city were executed by Shiite militiamen helping to retake the city.

To the north, take a video tour of the Mosul Dam—which officials have been warning for months is at risk and, if destroyed, could dramatically alter the fates of six million Iraqi citizens. More from War Is Boring, here.

GTMO to stay open for business. Looks like the Obama administration is passing on its ambition to close the detention facility at Guantanamo Bay, Cuba, through the use of an executive order, Reuters reports this morning.

Simmering conflict on the east African coast. Eritrea is accusing Ethiopia’s army of attacking its territory. “The TPLF regime has today, Sunday 12 June 2016, unleashed an attack against Eritrea on the Tsorona Central Front," the Information Ministry said in a statement around midnight. TPLF refers to Ethiopia's Tigrayan People's Liberation Front, one of the four parties making up the ruling coalition, Reuters reports. “A resident on the Ethiopian side of the border reported hearing the sound of explosions on Sunday and saw Ethiopian troops moving in the area. Eritrea, which won independence from Ethiopia in 1991, fought a bloody border war with its larger neighbor between 1998 and 2000. Tensions between the Horn of Africa nations persist.”

Lastly today: A #LongRead on Russian ambition throughout the ages: Get to better know the rise and fall of the Russian empire—and how President Vladimir Putin actually has far fewer options than his recent revanchist foreign policy suggests. This excellent deep-dive comes from Princeton historian Stephen Kotkin, writing in Foreign Affairs. Worth the click, here.