In the aftermath of the Pulse nightclub shooting in Orlando, Florida—an attack that claimed 50 lives—much has been made about the shooter's 911 call in which he pledged allegiance to the so-called Islamic State.

But homeland security expert Juliette Kayyem said it's important to consider the role that other allegiances and hatreds—including homophobia—played in the attack.

"He was ISIS-inspired; he was al-Qaeda inspired, because he referenced the Boston Marathon bombers; he was Hezbollah-inspired, because he was committed to them...he is LGBT-hatred inspired," she said.

"We're always looking for this thing that's, 'Oh, ISIS is responsible, this ideology is responsible,'" Kayyem continued. "But five minutes of researching this guy and you know: he was inspired by every hatred."

Those complicated overlapping factors, said Kayyem, are a reason to focus on how Mateen was able to carry out these murders just as much as the why behind the attack.

"You can focus on the motivation as long as you want, but you also have to focus on the means," she said.

Kayyem said the lack of communication between law enforcement officials and gun sellers is a good place to start.

"Our gun laws are indefensible," she said. "That the FBI wasn't authorized to even notify the gun dealer that this guy was under a suspicion was a victory to the NRA and their supporters, but a loss to the 50 people we lost yesterday and their families."

"It's ridiculous," she continued.

To hear more from homeland security expert Juliette Kayyem, tune in to Boston Public Radio above.