Jason Oppenheim’s stolen car mystery just got a little clearer — new surveillance footage shows a possible suspect and the exact moment his ride was stolen … and TMZ’s got the video.

Check the clip … a white pickup truck pulls into the “Selling Sunset” boss’ West Hollywood office parking lot on March 16, stopping just behind his $500K Rolls-Royce, before the driver hops out and casually walks up to the luxury vehicle.

Next thing you know — the Rolls is seen pulling out onto the street … with the truck trailing a few cars behind … pretty strong sign this wasn’t a solo job.