El DeBarge Won't Be Charged With Drug Possession

According to official D.A. documents, the case was rejected due to insufficient evidence.

TMZ broke the story ... DeBarge was arrested on Tuesday for felony possession of narcotics with intent to sell -- the singer's third drug arrest since 2001.

According to the docs, police officers noticed DeBarge and another man speaking on the street -- and for some reason, decided to search them ... without giving a reason why.

After searching them and coming up with nothing -- cops claim they perused the surrounding area ... and found a baggie of rock cocaine hidden under a nearby car.