By Greg Argos

ORLANDO, Fl. (CBS) — One day after the deadliest mass shooting in U.S. history, the FBI confirms the gunman, 29-year-old Omar Mateen, a U.S. citizen, may have been inspired to kill by ISIS.

Forty-nine people were killed and more than 50 others were wounded early Sunday morning when Mateen opened fire inside Pulse Nightclub in Orlando Florida.

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“The one thing we can say is that this is being treated as a terrorist investigation,” said President Barrack Obama. “It appears that the shooter was inspired by various extremist information that was disseminated over the internet.”

And as the federal investigation is in its infancy….

“There is a strong indication of radicalization by this killer and a potential inspiration by foreign terrorist organizations,” said FBI Director James Comey. “We are spending a tremendous amount of time, as you would imagine, trying to understand every moment of this killer’s path to that terrible night in Orlando, to understand his motives, and to understand the details of his life.”

Orlando, nicknamed “The City Beautiful,” is right now the city full of sorrow.

“It hasn’t quite quite hit me yet,” said Christopher Hansen, who witnessed the shooting, “but it’s going to.”

Hansen was inside Pulse when the first shots rang out and watched one the 49 victims die beside him.

“You hear gunshots that are not part of the music, you think our music, it’s like you look over, you see bodies dropping. You hear screaming. Blood everywhere,” he said.  The guy next to me is shot. He goes down. I go down. I’m going down. I dropped my way down and crawled my way to the back, and I had to just stay down and stay low, and once I felt the cement of the patio, I knew I was outside.”

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Hansen managed to escape, but still came back to help the wounded.

Others like Michael Hoffman, originally from Philadelphia, are also counting their blessings.

“We left about 12(a.m.),” Hoffman said. “Something told me, get out of here. Something is about to happen. God probably sent a message down from heaven saying just get out of this club.”

On Monday, neighbors like Don Amato, were helping those who are mourning lost friends and loved ones.

“This is a really close-knit neighborhood,” Amato said. “I see patrons all the time that go to the Pulse.”

Amato lives just feet from the club and is allowing people who want to leave a memory behind to get as close to where their loved ones died as possible.

“I said come with me. I live down the street. I’ll get you in there,” he said. “As far as I’m concerned, you’re my friends.”

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