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.

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.

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 … dropping a bombshell that he works for a celeb with “high status.”

Police said hard drives with Beyoncé’s unreleased music, set lists and footage plans for her “Cowboy Carter” tour were in the missing suitcases.