Goodell's Dead WRONG -- Casino Could Legally Have Given NFL Rice Elevator Video

Roger Goodell made a very bad assumption when he chose not to contact the casino to request a copy of the Ray Rice elevator video -- because law enforcement tells TMZ Sports ... that would have been perfectly legal.

Goodell said Tuesday he did not contact the Revel Casino because it was his understanding "the casino is prohibited from turning over material to a third party during a law enforcement proceeding" -- namely the criminal case against Rice.

But Paul Loriquet, the Director of Communications for the New Jersey Attorney General, tells TMZ bluntly, "No, it's not illegal."

To be clear ... our question was very specific: "Is it illegal for the casino to show or provide this material to a private entity in an ongoing investigation." His answer, "No, it's not illegal."

Mind you ... the NFL has some of the best lawyers in the country. It's inconceivable they didn't do basic legal research to either validate or invalidate Goodell's assumptions.