Denver Police have begun reviewing surveillance video taken from inside Sports Authority Field at Mile High as authorities step up the search for a man who vanished from the Denver Broncos' home stadium during Thursday night's game against the San Diego Chargers. 

Authorities told KDVR that they do not suspect foul play in the disappearance of 53-year-old Paul Kitterman, of Kremmling, Colo. 

Kitterman was attending the game with his son, Jarod Tonneson and two family friends. Kitterman and Tonneson had tickets in the stadium's south bleachers section that were separate from friend Tia Bakke and her boyfriend. The four met on the stadium concourse at halftime. At that point, Bakke told KUSA, Kitterman's son went to use the bathroom and Bakke and her boyfriend returned to their seats. As the group broke up, Bakke said Kitterman told them, "We'll see you after the game."

When Kitterman's son Jarod Tonneson left the restroom, he returned to his seat, but Kitterman never rejoined him. After the game, Tonneson met Bakke and her boyfriend, believing that Kitterman had gone to sit with them. Once they realized that Kitterman was missing, the trio began a prolonged search for him.

"We were looking everywhere in parking lots, trees, bushes, anywhere we could think of," Tonneson told KDVR.

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"We were at the stadium until one in the morning looking for him," Bakke told KUSA. 

Police said Monday that someone spotted Kitterman in the stadium during the third quarter of the game, but they could not specify the location. 

Bakke said Kitterman, not known to be a "technology guy," had only about $50 cash in his possession when they went to the game and was not carrying a cell phone or credit cards. He does not have any known medical conditions or issues with drugs or alcohol, she said.

"This is just so not characteristic of Paul," Bakke told 9News.com. "Paul is one of the most loyal, responsible people you'll ever meet in your life. He would never, ever just leave you hanging and especially his son. He would never leave Jarod."

Anyone with any information about Kitterman’s location is asked to call Denver Police at (720)913-2000.

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