DENVER (CBS4)– An Oregon man who was found guilty in September of sexually assaulting a woman at Denver International Airport will spend at least the next six years in prison.

Former Marine Noel Bertrand, 27, was found guilty of sexual assault with force in September and could face life behind bars. He was sentenced six years to life in prison on Friday afternoon.

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Bertrand, of Portland, committed the crime in a largely deserted A Concourse just after midnight on April 12, 2011. He met the 22-year-old victim at an airport restaurant after they both missed flights.

The victim was in court with her father and talked to CBS4 after the sentencing.

“I have yet to understand the full brevity of what it’s affected,” she said. “I’m just trying to keep my head above water.”

Bertrand’s lawyer said he still maintains his innocence and that will hurt his chances of getting out of prison early.

“He was given a six-year sentence, but I’m here to tell you that’s essentially a life sentence in Colorado, because Mr. Bertrand, based on principal, will not go into a therapy session and admit that he did this, which means they won’t release him,” Bertrand’s lawyer Wadi Muhaisen said.

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Surveillance video showed Bertrand and the woman walking together in the concourse. It didn’t show the assault that occurred 30 minutes later at a gate.

During the trial prosecutors say Bertrand aggressively forced the woman into sexual acts, but the defense said the two engaged in consensual “rough sex.” They also said she never called out for help or screamed. Prosecutors said she couldn’t talk because she couldn’t breathe due to his force and an asthma attack.

The victim had to describe the rape in detail on the stand. She said while they were at the deserted gate Bertrand asked if he could kiss her and she said “no.” She said that’s when he became violent, forceful and demanding. She said Bertrand told her she was his sex slave and that he was going to teach her to feel pleasure from pain. She told the court he pinned her head to her shoulder by grabbing her hair.

“He kept his hands around the drawstrings so I was unable to breathe. I was starting to cry and I couldn’t move. He kept telling me I was going to learn pleasure from pain,” the woman said. “Every time I tried to move he kept hitting my head on the ground.”

She said Bertrand eventually got her sweatpants down and raped her. She said he slammed her head to the ground so many times to keep her subdued that she became dizzy, had blurry vision and trouble hearing.

Two Frontier Airlines airplane mechanics witnessed part of the incident through the concourse window and ran inside and eventually stopped Bertrand and called police.

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“I haven’t been able to say a for sure ‘thank you’ to the mechanics,” the victim said to CBS4. “So, if you are watching, I really do appreciate what you did. If it weren’t for you, I would be here to say ‘thank you.’ I do really appreciate that.”