Taylor Swift‘s rear end sits right smack in the center of a slander allegation brought against the “1989” singer.

Former Denver DJ David Mueller, who was fired after being accused of groping Swift’s butt, has filed an amended complaint in his lawsuit against her, tacking on counts of slander against Swift and others.

Mueller filed suit in September, saying he was fired after being accused of “grabbing Ms. Swift’s bottom” at a meet-and-greet at Denver’s Pepsi Center in June 2013. The radio personality, who goes by the professional name “Jackson,” has adamantly denied the accusation.

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In new papers filed in federal court in Colorado, Mueller says Swift and others “orally published and/or caused to be published to third parties multiple statements that Plaintiff Mueller lifted Taylor Swift‘s skirt and grabbed her bottom during a photo session, or statements in substantially similar words.”

The statements, the amended complaint claims “were false at the time they were made.”

At the time of the lawsuit’s filing, a spokesperson for Swift told TheWrap that KYGO, the radio station Mueller worked for, “was given evidence immediately after the incident. They made their independent decision” to fire Mueller.

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Swift has filed her own countersuit, asserting that the incident did in fact happen, and it left Swift “surprised, upset, offended and alarmed.”

Mueller is seeking unspecified damages.

Pamela Chelin contributed to this report.