Airport employees told police they saw Collins touching himself, KDVR reported, a claim Collins disputed to the Post. He told the newspaper that he was on the phone and preparing for a shower after spending more than 30 hours straight awake and at work when the incident happened.
"It was a beautiful morning and I opened the curtains to my window," he told the Post. "I couldn't see the terminal."
United Airlines spokeswoman Erin Benson said in a statement to KUSA that the airline is cooperating with authorities. The company also launched an internal review of the incident. Collins has been removed from his duties as the internal investigation continues, KUSA reported.
He is expected to appear in court Dec. 5, according to KMGH-TV.