At the time of the alleged incident, Mueller was a radio DJ for country music station 98.5 KYGO in Denver on the Ryno and Jackson morning show, going by "Jackson." He was invited to the June 2, 2013 meet-and-greet as part of his job, and that is where the alleged groping incident took place.
He was terminated from his position on June 4, 2013, two days after the alleged incident with Swift. KYGO claims Mueller was fired for violating the morality clause of his contract after it says it independently determined that he lied about the incident, changed his story and inappropriately touched Swift.
Swift alleged that Mueller put his hand up her skirt and grabbed her bare bottom when they took a photo together during the pre-concert fan meet-and-greet on the Denver stop of her Red tour. Once the meet-and-greet was over, she says she alerted her mother as well as others on her team about what had allegedly happened. TMZ published the photo in question last November.
Swift never reported the alleged incident to Denver police, but according to court papers, Swift's radio promotions director, Frank Bell, reported the alleged incident to KYGO.
Mueller, who was 51 at the time while Swift was 23, has denied the allegations, and claims that Swift and her team got him fired for no good reason. He also claims that later in the evening on the night of the concert, he was berated and thrown out by security.
"He reached under my skirt and grabbed my a** right when I was having to pose for a photo, and it felt intentional that that would be the time he would choose to do it," she claimed during her deposition about a photo taken with Mueller and his girlfriend at the time.
"It's impossible for me to pick one specific moment that it was happening because it happened in a series of moments, so one of the moments when it was happening, in progress, was the moment we were posing for the photo and when the photo was being taken, but that was not the only moment that he was grabbing my a**," she alleged.
What is Mueller suing for?
Mueller sued Swift on Sept. 10, 2015 -- two years after the alleged incident -- claiming her accusations that he inappropriately touched her were false and cost him his $150,000-a-year job and future career opportunities. After Mueller’s employer was informed of Swift's accusation, he was terminated from his job.
Mueller is seeking up to $3 million in damages.
Swift countersued Mueller one month later for assault and battery. Court papers allege that "Mueller did not merely brush his hand against Ms. Swift while posing for the photograph: he lifted her skirt and groped her." She added that he waited an "unreasonably" long time to file his suit.
She is asking that attorney's fees and costs be paid for by Mueller along with compensatory damages to be proven at trial. Swift says she'll donate any money won from the lawsuit to "charities dedicated to protecting women from similar acts of sexual assault and personal disregard."
Who will testify at the trial?
Both Swift and her mother, Andrea Swift -- who's also named as a defendant in the case -- will testify at some point during the trial, according to the final pretrial order. Greg Dent, Swift's bodyguard who was present when the photograph was taken, is also expected to testify, as well as her photographer, who took the photo in question that captured the alleged assault.
How long is the trial expected to last?
A jury will hear both sides of the case beginning next week. The trial is expected to last nine days; likely until Aug. 17.
U.S. District Court judge William Martinez will be presiding over the trial at the Alfred A. Arraj courthouse in Denver.
Swift fans can technically be allowed in the courtroom, as 32 seats are designated for members of the public -- not media -- and 75 seats will be made available in the public overflow location in the courthouse. However, shirts bearing her name or anything of her likeness will not be permitted.