No Smoking Gun Video In Robbery Case

Cops are NOT in possession of video showing Deandre Baker and Quinton Dunbar robbing people at gunpoint at a cookout in FL ... but investigators are scouring the neighborhood hoping to find something ASAP.

Multiple people involved in the investigation had told us they were confident there was video from the May 13 incident -- but a spokesperson for the Broward County State Attorney's Office tells us straight-up there's no video, "not that I'm aware of."

One person involved in the case tells us cops are making an effort to speak with people in the vicinity to find out if the incident was captured on home surveillance video, including Ring doorbell cameras ... and no, TMZ Sports has not seen…