DENVER – The defense team for singer Taylor Swift will get to cross-examine the man accused of grabbing her buttocks before a Denver concert in 2013 over how a tape of the man speaking with his radio station bosses about the incident disappeared while he was pursuing legal options in the case.

The trial involving Swift and the man, former KYGO radio host David Mueller, is set to begin Aug. 7 in the U.S. District Court of Colorado in Denver.

Judge William J. Martinez on Wednesday decided that the famed singer’s defense attorneys will get to cross-examine Mueller over how the full tape disappeared so the jury can decide if he acted maliciously and destroyed evidence of the full tape himself, or whether a series of accidents and misplacements ended in the full tape disappearing.

Mueller was fired from his job in early June 2013—days after a member of Swift’s security team claimed that Mueller had grabbed her buttocks underneath her skirt while taking a photo together ahead of a concert at the Pepsi Center.

He sued Swift and some members of her team in September 2015, claiming they slandered him and forced his firing without cause, though the radio station said it did its own internal investigation before firing Mueller.

And Swift filed a counterclaim months later calling Mueller’s claims that it was a different KYGO employee who actually touched Swift’s buttocks “specious” and called for a jury trial to settle the back-and-forth allegations.

Swift’s attorneys filed documents in late June and early July claiming that Mueller destroyed the secret tape he had made of the conversations involving his superiors.

Judge Martinez’s decision on those motions came Wednesday, but he stopped short of declaring Mueller had committed an “adverse interference” in the case when the tapes went missing.

Mueller secretly recorded the meeting, which is legal under one-party consent rules in Colorado, with his superiors on June 3, then edited the full two-hour tape into clips, which he sent to his attorney.

Mueller kept the full audio file on his computer and on an external hard drive, he testified. But at some point after making the edited clips, he spilled coffee on his computer, then went and got a new one without saving its hard drive. The judge’s ruling says he got the new computer sometime in 2015.

And Mueller also claimed when he was deposed that his external hard drive “stopped working” and that he threw it away “because it was junk.”

Thus, the full audio of the meeting has never been heard by anyone except for Mueller, and the meeting between him and his superiors plays a central part in the case.

Judge Martinez found that the full tape would have helped Swift’s team in discovery and possibly in the upcoming trial, but could not say, based on the evidence, that Mueller lost or destroyed the full tape by doing so “in bad faith”—a requirement for proving an adverse interference.

Instead, the judge decided he had lost or destroyed the tape out of “mere negligence”—which is still a “sanctionable spoliation of evidence,” he wrote.

“Although the Court declines to make a finding that Plaintiff acted in ‘bad faith’ in the sense that he intended to destroy evidence, it also cannot characterize the loss or destruction of evidence in this case as innocent, or as ‘mere negligence,’” Judge Martinez wrote.

Judge Martinez said that Mueller should have known that legal movement in the case was “imminent” and thus should have known he would be require to preserve evidence relevant to the case.

“[I]t is quite likely that the reason Plaintiff secretively recorded his conversation with Call and Haskell (his former employers at KYGO) was because he knew that some form of adversarial legal action was likely to follow,” Martinez wrote. “Moreover, Plaintiff later edited the audio file in order to send ‘clips’ to his own attorney…because Plaintiff himself was actively considering [litigation].”

Because of this, Judge Martinez wrote, Swift’s team was “prejudiced by the loss of evidence,” because not having access to the recording limited their “ability to explore whether Plaintiff has or has not ‘changed his story.’”

The judge wrote that Mueller “failed to take any number of rather obvious steps to assure that this evidence was not lost.”

“While the spill of liquid on his laptop may have been Plaintiff’s fault, it was an entirely foreseeable risk,” Judge Martinez wrote. “Indeed, the same thing had happened to Plaintiff’s previous laptop not long before…Plaintiff could and should have made sure that some means of backing up the files relevant to litigation was in place, but this was not done.”

Judge Martinez also chided Mueller for being “unjustifiably careless” in handling the audio file after seeking claims of $3 million against Swift for defamation.

“Given these claims, it is very hard to understand how he spent so little time and effort to preserve the very evidence which—one might think—could have helped him to prove his claims, and why he evidently responded with nonchalance when that evidence was lost,” Judge Martinez wrote.

As such, he said that giving Swift’s defense the chance to cross-examine Mueller would give the jury the best opportunity to determine whether Mueller got rid of the tape on purpose, as both of his KYGO superiors are already expected to testify at the trial.

The judge wrote that he didn’t want to “put too heavy of a thumb on the scale” against Mueller’s claims, and that giving Swift’s attorneys the chance to cross-examine him would give her team “the benefit of allowing the jury to make its own assessment” of Mueller’s actions.

“The Court has little doubt that if the jury concludes Plaintiff acted with bad faith or an intention to destroy or conceal evidence, they will draw their own adverse inferences,” Martinez wrote.

A final pre-trial preparation conference in the case is set for July 21. The trial is set to begin Aug. 7 at 8:30 a.m. and is scheduled for nine days.

Swift will be in court during the case, and has said in the past that if the jury finds in her favor that she’d donate any money to charities whose missions are to protect women from sexual assault.