Internet provider Cox Communications has asked a Virginia federal court to dismiss the copyright infringement lawsuit filed by several music companies last year. The case relies on evidence collected by piracy tracking firm Rightscorp, which Cox says is unusable after the anti-piracy outfit destroyed older versions of its piracy tracking code.

Last year BMG Rights Management and Round Hill Music sued Cox Communications arguing that the ISP fails to terminate the accounts of subscribers who frequently pirate content.

The companies, which control publishing rights to songs by Katy Perry, The Beatles and David Bowie among others, claim that Cox gave up its DMCA safe harbor protections due to this inaction.

The case revolves around data gathered by Rightscorp and Cox believes that the anti-piracy company is the driving force behind it, in part to retaliate for Cox’s refusal to forward their infringement notices.

Both parties have been preparing for trial but Cox now believes that one isn’t needed. A few weeks ago the court ruled that Rightscorp spoiled evidence by failing to preserve historical versions of its piracy tracking code. As a result, Cox insists that the entire case should now be dropped.

According to the ISP all evidence of direct copyright infringement relies on Rightscorp’s system. Without the option to assess the accuracy of the tracking technology, it’s impossible to review the reliability and accuracy of the accusations.

“Cox cannot analyze, and the jury cannot assess, the operation or accuracy of Rightscorp’s pivotal systems. That is because Rightscorp intentionally destroyed every version of its technological systems that existed prior to July 15, 2015,” the ISP writes in its motion (pdf).

According to Cox’s legal team the copyright holders and Rightscorp’s failure to keep track of the code changes did not occur by accident.

“Despite actively planning this lawsuit for over three years, Plaintiffs and their litigation agent, Rightscorp, knowingly and intentionally failed to preserve the most critical evidence in the case.”

“As a result of that misconduct, as Judge Anderson found, it is literally impossible for Cox or the jury ‘to know how the Rightscorp system operated during the relevant time period’,” Cox adds.

While Magistrate Judge Anderson ruled that Rightscorp did indeed spoil crucial evidence, he referred a decision of specific evidentiary sanctions to District Court Judge O’Grady.

In its motion Cox is clear about what the final decision should be. The ISP sees a dismissal of the entire case as the most fitting outcome. It’s impossible for a jury to review how reliable some of the most crucial evidence is, so the case should be dismissed, Cox argues.

“In these circumstances, the most appropriate sanction is dismissal, particularly given that Judge Anderson’s factual findings effectively defeat Plaintiffs’ claims in

any event. For the many reasons Cox addresses below, this case should end now,” the motion reads.

The motion will be discussed at an upcoming hearing. In a reply, BMG Rights Management and Round Hill Music have already objected to the request, describing it as an untimely motion for summary judgment.

Update November 20: Cox’s motion was denied.