Seattle Seahawks cornerback Quinton Dunbar claims he did NOT pull out a gun and rob people at a Florida cookout this week ... and claims he's got 5 witnesses who will back up his story.
Dunbar's attorney Michael Grieco tells TMZ Sports ... 5 witnesses came to his office Friday morning and signed sworn affidavits insisting Dunbar was NOT involved in the May 13 incident.
"My client is innocent," Greico tells us ... "Never been arrested before. This is a man who's never been in handcuffs, never been in trouble. He didn't do anything wrong.