Bewilderment. Horror. Sheer incomprehension.
How could a lone gunman, apparently inspired by Isis, and known to the FBI, make his way into a popular gay venue on a busy weekend night and leave devastation and murder in his wake, before he was eventually shot and killed by police? Furthermore, what drove him to do so?
With the death toll having reached reached 50 - although this is feared likely to rise, with 53 further people injured - and the attack, launched in the early hours of Sunday morning, for many calling to mind last November’s shootings at the Bataclan Theatre in Paris, there were more questions than answers.
Police named the the gunman as 29-year-old Omar Mateen, an American citizen who lived in Fort Pierce, Florida and whose whose parents are from Afghanistan. He had been able to buy his weapons, legally, in the last few days.
While police said they were treating the incident as an act of terrror, it was unclear whether the young man armed with a semi-automatic rifle, a handgun and possibly an explosive device, was directed by Isis, or merely inspired by the group or others to act.
“I’m just shocked, stunned. We heard the explosion,” said Elizabeth Kohl, who lived close to scene and who drove one of those injured to hospital.
The Isis-linked Amaq news agency reported that Mateen was a fighter for the group, but officials warned that this was unconfirmed.
Officials said he had previously been on the radar of investigators, he had been cleared and was not currently being investigated. Local media said the man - whose wife said he had beaten her before they got divorced - had made several declarations of support for Isis.
His father, Mir Seddique, told NBC News his son had become angry a couple of months ago when he saw two men kissing in Miami, and he believed that could be related to the shooting. He said the attack on the nightclub had “nothing to do with religion”. However, it has been revealed that 911 calls involving the shooter took place before the massacre, in which he talked about the so-called Islamic State.
Many will seize on the incident as another example of the threat posed to the US by domestic Islamic terror and those who self-radiclalise.
“What is clear is he was a person filled with hatred,” said President Barack Obama, speaking at a press conference following the attack.
“We know enough to say that this was an act of terror and an act of hate," he said. "And as Americans, we are united in grief, in outrage, and in resolve to defend our people.“
The presumptive Republican presidential candidate, Donald Trump, was quick to condemn President Obama for not referring to “radical Islamic extremism” in his speech, calling for him to “immediately resign in disgrace” on Twitter.
Reports said that a police officer working as a security guard inside the club exchanged fire with the suspect at about 2am, according to Reuters. A hostage situation developed in the club and three hours later SWAT team officers stormed the building before shooting dead the gunman. It was unclear when the gunman killed the victims. There were thought to have been as many as 300 people inside the nightclub, which has operated in the centre of Orlando since 2004, and was established to keep alive then memory of the owner’s brother who died of Aids.
“Do we consider this an act of terrorism? Absolutely,” Danny Banks, special agent in charge of the Florida Department of Law Enforcement, told reporters. “Whether that is domestic terrorist activity or an international one, that is something we will certainly get to the bottom of.”
Asked if the FBI suspected the gunman might have had inclinations toward militant Islam, including a possible sympathy for Islamic State, Ronald Hopper, an assistant FBI agent in charge, told reporters: “We do have suggestions that the individual may have leanings toward that particular ideology. But right now we can't say definitively.”
US Senator Marco Rubio of Florida told CNN he understood that the gunman had worked for a security company and so would have undergone some background checks.
“Over the next couple of days they're going to be looking to see where this individual was inspired to carry out this horrifying act of terrorism,” said Mr Rubio said. “I think we're going to be talking about a very different kind of case here soon.”
Reports said that Mateen, had two licences to carry a concealed weapon. He held dozens of people hostage, some of them hiding inside the lavatories of the club, until police stormed the venue, using an armored vehicle and stun grenades. The survivors escaped under the cover of what the police called the two “discretionary explosions.” By 5am, the gunman had been killed.
The club itself posted a message on its Facebook page about 3am that read: “Everyone get out of pulse and keep running.”
It added: “Please keep everyone in your prayers as we work through this tragic event. Thank you for your thoughts and love.”
The wounded were taken to three hospitals in the area. Most were taken to Orlando Regional Medical Centre, the area’s main facility, where anxious friends and family members gathered for news on the injured.
The Pulse nightclub was known as a friendly, welcoming club that was part of the community and had never experienced - or caused any trouble.
“I feel like this an attack on the whole LGBT community,” said Giancarlo Sola who said he had been to the club several times. “I don’t know about Isis. I don’t think this was Isis - this was a hate crime.”
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