DENVER -- Surveillance video obtained by 7NEWS from Concourse A at Denver International Airport shows the response to a reported sexual assault.

A woman accused Noel Bertrand of sexually assaulting her in the early morning hours on April 12. He was charged with felony sex assault in a Denver County court Tuesday afternoon. The woman told 7NEWS that she missed her connecting flight from Illinois and met Bertrand at a bar in the food court.

The video shows Concourse A from a surveillance camera positioned in the middle of the ceiling between two sets of moving walkways. The camera points toward the food court and shows gates A42 and A44 on the left.

What The Surveillance Video Shows

At 11:58 p.m., the video shows two people, a man and a woman, get off the moving walkway and walking to the area between gates A42 and A44.

For about 15 minutes, the video shows people walking away from the camera, apparently having just gotten off an arriving plane.

At 12:20 a.m., a female employee can be seen pushing a cart right near gates A44, then A42. She does not appear to look in the direction of the gate areas.

At 12:29 a.m., a person stops between the two sets of moving walkways, looking in the direction of the gate area where the alleged assault was occurring. That person then continues on to the moving walkway.

At 12:30 a.m., an airport employee walks toward gate A44, while another employee can be seen coming down the moving walkway toward the gate area.

At 12:31 a.m., one of the employees waves his hand in the air in the direction of a bicycle police officer.

At 12:32 a.m., the camera zooms into the gate area, but the view is obstructed by an awning overhead. Over the next 30 minutes, the camera shows another bicycle officer arriving, as well as an airport cart. Numerous personnel appear at the scene.

What The Surveillance Video Doesn't Show

The video never shows Bertrand taken into custody by police. It also doesn't show the alleged attack, and what it may have looked like to people walking by.

Last week, 7NEWS went to Concourse A and saw nearly a dozen cameras in the area but did not see any directly above the area near Gates A42 and A44.

Two Frontier Airlines mechanics told 7NEWS that they saw the attack from outside on the tarmac. They came inside the concourse and pulled the man off the woman.

The woman told 7NEWS that airport employees walked by and saw the attack, but didn't do anything. A DIA spokeswoman told 7NEWS last week that airport employees did as they're trained; they reported the attack to police or intervened. On Tuesday, a DIA spokeswoman told 7NEWS that airport personnel viewed the surveillance video and stand by the comment that employees did as they're trained.

An aviation professor at Metro State College and who also served as assistant security director at DIA in the 1990s said adding security cameras to all areas of the airport isn't a likely solution.

"(That) doesn't make the situation any less tragic. What it means is that's probably not the right solution," said Jeff Price. "And I can tell you right now, at every airport across the country, they're addressing this issue. It opens up the aviation security spectrum to include crime."

Price said it's impossible to know what airport staffers could see or hear during the half hour after the couple had moved beyond view of the security cameras but said staffers see plenty of unusual things late at night.

"People sleeping in the airport. Sometimes couples are making out in the middle of the night," Price said. "You do have some background noise to cover things."

Price said he believed there are security cameras closer to A42 and A44 but that they're more likely used to look for terrorists of thieves.

"It's all really about access," Price said. "They're watching for illegal access to the airfield, not an act of violence."

A spokeswoman told 7NEWS she didn't know if other security video was taken of the alleged incident and couldn't say if the area near A42 and A44 had cameras closer than the one seen in our video.