Cuba Gooding Jr. allegedly grabbed a handful of butt at a party in Los Angeles and the woman reported him to police, but prosecutors didn't feel they had enough evidence to charge the actor with a crime ... law enforcement sources tell TMZ.
Our sources say Cuba's alleged butt-grabbing went down at a shindig in L.A. sometime in the past year -- the woman filed a police report and cops investigated. We're told the case was turned over to the L.A. City Attorney for misdemeanor sexual battery, but the City Attorney rejected the case in August because of a lack of evidence.
Cuba's attorney, Mark Heller, tells TMZ ... "Cuba doesn’t recall this case. He’s out every night of his life. He meets so many people. He interacts with so many people -- he can’t remember all the people he meets."
This previously unknown allegation against Cuba comes on the heels of Tuesday's 4-count indictment against him in New York, where he's facing one count of forcible touching and one count of sexual abuse in the third degree -- both misdemeanors -- related to his new accuser, and the same charges for his original accuser from this summer's rooftop bar incident.
Cuba, who turned himself in to cops in NYC before being released Tuesday, has pled not guilty to those 4 charges.