Lupita Nyong'o's Stolen Dress ... Surveillance Cams So Bad ... Ray Rice Could Have Skated

The now-famous $150,000 dress that was stolen from Lupita Nyong'o's West Hollywood hotel room is no closer to being found because TMZ has learned the surveillance video is a bust.

Law enforcement sources tell us detectives have reviewed video from The London West Hollywood and it shows nothing leading them to the thief.

A big problem ... the security cameras in the hotel are spotty and there was nothing trained on the area surrounding the door of Lupita's room.

One source put it this way ... "If Ray Rice did what he did at The London, he would have gotten away with it."

Cops are stumped as to how the dress was taken. One source says it was too "long and stiff" to wear with something over it. It could have been placed in a hamper or a bag ... they just don't know.

They also don't know if it was an inside job or if someone who had access to Lupita's room stole it.

What they do know is this ... it's definitely gone.

A photog got Lupita at JFK airport early Friday, but she was mum.