Vesta Williams -- Prescription Pills Found at Death Scene

Multiple bottles of prescription pills were found in the El Segundo, CA hotel room where R&B singer Vesta Williams died ... law enforcement sources tell TMZ.

We're told "several bottles" were discovered -- some empty.

Law enforcement sources tell us officials first received a call related to Vesta's death around 6PM Thursday night.

Sources tell us the death is being treated as either an accident or suicide, but not a homicide.

The coroner won't know if drugs played a part in her death until the toxicology reports are in -- and that could take 6 weeks.