The Shake It Off hitmaker fired back in a countersuit, accusing him of sexual assault and battery. He is seeking at least 3 million dollars (£2.3 million), saying the allegation cost him his job and reputation.
Swift's attorney questioning Mueller about his past job in Minneapolis, where he was let go.
"You've seen other photos...no one else had their photos near her rear end", Baldridge says. "Any woman-rich, poor, famous or not-is entitled to have that not happen".
Taylor Swift's counter-lawsuit argues that the case will "serve as an example to other women who may resist publicly reliving similar outrageous and humiliating acts".
The trial is expected to last about two weeks.
"Right as the moment came for us to pose for the photo, he took his hand and put it up my dress and grabbed onto my ass cheek and no matter how much I scooted over it was still there" Swift states.
According to his suit, Mueller is accusing the singer of "intentional interference with contractual obligations" and "interference with prospective business relations" that led to lost wages.
Mueller did not sue his station KYGO or its parent company Lincoln Financial Media Co. of Colorado, after he was sacked June 4, 2013.
Swift testified at a deposition that she is certain Mueller intentionally grabbed her.
Swift, who is countersuing Mueller, wants damages in an amount to be proven at trial, but also a verdict that holds Mueller responsible for the alleged assault. She says she is only seeking $1. The eight-member U.S. District Court jury is now weighing both claims in a single trial. Swift's attorneys have pointed to that as evidence of the inappropriate touching, and noted that KYGO cited the photo as one reason for his termination.More news: Rich Coleman named interim caucus leader for BC Liberal Party
More news: Engineer behind controversial manifesto is out at Google
More news: Donald Trump defends national security adviser amid criticism from conservatives
Those devices in particular were said to possibly contain a lengthy recording with his boss, Robert Call, during which Mueller reportedly discussed changes to his story.
Also damning? In July, a judge sanctioned Mueller based on some particularly questionable behavior following the incident.
Because of Mueller's actions, attorneys will be permitted to ask him questions about the contents of the tape and the jury can factor Mueller's destruction of evidence into their final decision.
Andrea Swift was called to the stand on Wednesday afternoon as the case's second witness.
Gabriel McFarland, Mueller's attorney, said the photo was "awkward" but did not show any inappropriate, under-skirt touching as Swift has alleged.
Throughout Mueller's testimony on Wednesday, Swift listened attentively with her hands clasped in her lap.
Taylor Swift playing the first of two sold out shows at the Pepsi Center on her most recent tour for the album 1989. "It's not ruffled, rumbled, affected in any form or fashion".
Mueller continues to claim it was a "quick slide in" to get the photo and that he didn't touch Swift's bare bottom.
Taylor Swift is no stranger to making empowering statements, but she is using an unconventional method to send a message this week: a lawsuit.