Grooveshark bosses score an own goal.

The music industry has claimed another victory this week after a U.S. judge ruled that Grooveshark infringed on thousands of their copyrights.

In the end, it was a slip-up by the company’s CEOs that secured the ruling, reports the New York Times. The online music service had relied on the defence that the its activities were legal under the Digital Millennium Copyright Act, which protects websites that host third-party – and potentially infringing – material as long as they comply with takedown notices from copyright holders.

But a federal judge ruled on Monday that Grooveshark had indeed infringed copyright – because its own employees and bosses, including CEO Samuel Tarantino, had uploaded 6,000 songs without permission. These actions were considered direct infringments, so DCMA protection no longer applied.

The company was also found to have destroyed important evidence in the case, including lists of files that employees had uploaded. The next step in the case will be to determine the damages Grooveshark must pay. If that amount reaches into millions of dollars, it could spell the end for the service.

In the meantime, Grooveshark is facing two other copyright suits filed by music industry representatives. The case is the latest example of the music industry clamping down on online music services, with satellite broadcaster SiriusXM punished recently in a complicated case surrounding the USA’s tricky pre-1972 copyright laws.