DENVER
06/13/2013 12:32 pm ET | Updated Jun 13, 2013

Samuel Granillo, Columbine High School Shooting Survivor, Opens Up About Massacre (VIDEO)

In March, The Huffington Post began talking to teens and adults throughout the U.S. about their experiences with gun violence. This is one individual's story. You can read others here.

Fourteen years ago, on the morning of April 20, 1999, seniors Eric Harris, 18, and Dylan Klebold, 17, set off bombs, murdered 12 classmates and a teacher, injured 24 more, and then ultimately took their own lives at Columbine High School -- all in the span of 49 minutes, in what has remained one of the bloodiest mass shootings in American history.

Samuel Granillo was a 17-year-old junior at Columbine High School when the massacre occurred. Now 31, Granillo says he is still recovering from the psychological scars left from that day.

Tragically, on July 20, 2012, Granillo relived much of that pain when a gunman opened fire on an unsuspecting audience -- one that included several of his friends -- at the Century 16 theater in Aurora, Colo., during a midnight screening of "The Dark Knight Rises." Fifty-eight people were injured and 12 were killed, including Granillo's friend, 24-year-old Alex Teves.

In a detailed interview with The Huffington Post, Granillo opens up about what happened to him during the Columbine shooting and what continues to haunt him to this day, as well as the trauma of losing a friend to gun violence in another mass shooting so close to home.

Watch Part 1 of the Samuel Granillo interview (story continues below video):

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Granillo was one of 17 people at Columbine High School barricaded in an office near the school's cafeteria, where much of the massacre took place. The students quickly noticed that there was no lock on the office door, so Granillo shoved his toes into the bottom of the door and laid on the ground to use his body weight to wedge it shut.

"A couple minutes later the doorknob turns," Granillo recalled. "And it's just like in a horror movie almost, when you're trying to be quiet and the doorknob starts to turn and you know what's on the other side. And everyone in my room, which was a tiny office, started pushing on my knees and shoulders trying to brace me. We were fighting the door shut against the shooters."

Granillo says that it was a quiet struggle in that room trying to keep the door shut, and that there were no words exchanged between the 17 people hiding and the people they heard outside. He cannot be sure who was on the other side of the door, but assumes it was Klebold and Harris.

"It wasn't somebody looking for safety, it wasn't anyone saying, 'Please let me in, I need a place to hide' -- it was quiet and angry feeling," he said. The people outside the door managed to force it open a couple of inches, but never fired any shots at it.

And suddenly they stopped pushing, Granillo recalled. "They sort of gave up, I don't know what happened, but I could hear them talking outside the door and I don't know who else it would have been. It was the weirdest tone of voice -- it was so casual, there was no panic in the voice, they weren't angry. It was just two people talking.

"And the voices sort of faded away, and as they did, more and more gunshots and explosions started going off in the distance. We could sort of tell how far away they were from the distance of the noise, and when we felt they were far enough away, as fast as we could we built a barricade against the door with everything in the room."

For a tense three and a half hours, Granillo and the others in the group hid in the office, some talking on the phone to police officers outside the school. Eventually a SWAT team arrived to rescue them and help them escape.

Watch Part 2 of the Samuel Granillo interview (story continues below video):

Despite having heard the sounds of gunfire and explosions, they did not yet know exactly what had happened right outside the office walls. As they exited the room and headed toward a broken window to escape, Granillo says they began to take in the full scope of the tragedy that had unfolded.

"No one really knew what was going on," he said. "I'm thinking the whole time hopefully everything is okay, but I look up into the cafeteria and see it just destroyed: Tables are turned upside down, smoke everywhere, broken glass, flipped up chairs, puddles of water."

When Granillo stepped outside, he immediately saw a body at the bottom of the stairs at the side of the school. "I just stared at [the body], it didn't look like a person really, it sort of just looked like an animal on the side of the road -- you could see the humanity was gone, they had died before they even hit the ground."

Officials then began to let Granillo and other students still leaving the school run up a nearby hill to safety. "I run up the hill and I look down and there's a girl who had been killed laying on her back -- which was my friend Rachel. I didn't know that at the time -- and I almost tripped over her," Granillo said, referring to Rachel Scott, a 17-year-old student who was shot to death on the lawn along the west entrance to the school while eating lunch with friend Richard Castaldo.

"There were some cop cars nearby and that's how we eventually got away from the school, but that's not at all where it ended," he said. "The rest of the day was just filled with chaos trying to figure out what happened, who was okay, who got killed, trying to find parents, trying to piece stories together."

Granillo says he didn't find his mother until around 4 p.m. that day. "The second I saw her, I finally broke down and started crying. That's when I finally knew that I was safe, or felt safe."

The next month was a blur for Granillo. The combination of finishing school, going to funeral after funeral for murdered classmates, and making hospital visits for the wounded left him deeply traumatized.

He says that even though he loathes what Klebold and Harris did that day, he doesn't hate them as people. "No matter how hard I try, I can't bring myself to hate them. I hate what they did, what they did was scary, it changed my life, it destroyed others -- it was really awful. But I can't hate them as individuals. It's a hard thing for people to believe or understand."

He is still wavering on forgiveness.

"I don't know, that's a hard thing to forgive, but it doesn't mean I can't look past it. Forgiveness may be out of the question, maybe, but I just don't think forgiveness is the right word. It's more complex than that for me. Way deeper."

Granillo is currently working on a documentary about the Columbine shooting as told from the perspective of survivors. To learn more about the project, "Columbine: Wounded Minds Project," visit the "Columbine: Wounded Minds Project" website.

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