D.A. Rejects Dr. Dre's Gun Case After Citizen's Arrest

Dr. Dre just emerged victorious in the showdown with that guy who accused him of pulling a gun ... TMZ has learned.

Law enforcement sources tell us the L.A. County District Attorney has already rejected the case for insufficient evidence. As we first reported ... cops say they found NO gun on Dre after searching him Monday at his Malibu mansion.

Our sources close to Dre weren't the least bit surprised by the D.A.'s decision since the whole case was "ridiculous."

TMZ broke the story, a motorist who was blocking Dre's driveway off PCH insisted on making a citizen's arrest, claiming Dre pulled the weapon during a verbal dispute.

With the D.A.'s decision, this guy can officially ... forget about Dre.