Authorities in Seattle hope someone will recognize a man who, they said, was captured on video exposing himself to a teenage girl on a city bus.

The 15-year-old female victim took video of the suspect performing a lewd act on a city bus last month and turned the video over to police, said Myrle Carner, director of Crime Stoppers of Puget Sound.

"She looked over and saw the suspect exposing himself. He tried to engage her in conversation and she absolutely, obviously refused," Carner said.

"She took out her phone camera and actually shot some video and still shots" of the lewd act, Carner said. "When he was done, he went to the exit and left the bus."

Carner, a former detective, said the unidentified teen should be "commended" for her quick-thinking, but he wouldn't advise people to film predators.

"The other side of it is sometimes you can put yourself in a dangerous, precarious position by doing a direct confrontation like that," he said.

Jeff Switzer, a spokesman for King County Metro, said transit officials are working with police to investigate the incident.

"It's important for riders to pay attention to their surroundings on the bus or anywhere in public, for that matter," he said. "Our riders and our drivers and the police continue to work together to keep everyone as safe as possible."

Anyone with information about the case is asked to call the Crime Stoppers Tipline at 1 (800) 222-TIPS.

(Image Credit: KOMO/ABC News)