An arrest has been made in the theft of unreleased Beyoncé music ... but the tunes are still MIA.

Atlanta police tell TMZ ... Kelvin Evans was arrested for allegedly breaking into an SUV over the summer and taking the superstar's super important property. Gallery Launch Gallery Getty

As we told you ... cops responded to a parking garage in July on a report of a theft from a motor vehicle. Two of Bey's crew members -- a choreographer and a dancer -- told officers the trunk window of their rented Jeep Wagoneer had been damaged and two suitcases were stolen. Play video content

TMZ obtained 911 audio from the Atlanta PD ... you can hear one of Beyoncé's crew members explaining to the dispatcher there's "really, really important information" in the computers ... dropp

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