My car got stolen? Cadillac Catera. What should i do?

[Rustam S.]

Hi there! I parked my car at city parking lot and left with my friends on another car, when we came back there were no car and i think i dropped my keys or something, because i had no keys on me. I don't know what to do, its my brothers car it has one and a half insurance. What should i do? I already called police and opened claim. Its black Cadillac Catera. Please HELP!!!