Coral Gables detectives said a man parked his Jaguar in front of his home's driveway. There was a parked four-door BMW that he didn't recognize.
He was holding a bag with jewelry when he got off the car in the area of Ingram Highway and Douglas Road near Coconut Grove, according to detectives.
The victim told police officers that a robber wielding a hand gun jumped out of the white BMW and chased him when he started running. The robber swiped the bag when he dropped it.
Officer Kelly Denham released an image from surveillance video on Tuesday. It showed the armed suspect was wearing long dreadlocks in a bun during the time of the midday Saturday robbery.
Detectives believe the robber is in his late teens or early 20s, and they were asking anyone with information to call 305-442-1600 or Miami-Dade Crime Stoppers at 305-471-8477.