SOUTH PORTLAND – A 29-year-old woman who accused a police officer of sexual assault is behind bars after being charged with making up the story.

Shannon Wehkoja, whom police described as a transient from Massachusetts, was arrested Friday and charged with perjury, false swearing, filing a false report, violating a condition of release and possession of drugs.

Police Chief Edward Googins said Wehkoja accused Officer Ed Knutson of sexually touching her while taking her to jail after arresting her on a drunken-driving charge on Jan. 1.

But a video from Knutson’s cruiser documented the trip and showed that Wehkoja made up the story, Googins said.

“The concern that the department had was, these charges could have been career-ending for the officer and they were totally false and fabricated,” he said.