Rosario Dawson Finds 26-Year-Old Cousin Dead in Her Home

Rosario Dawson's cousin died after the actress found her unconscious last week ... TMZ has learned.

Law enforcement sources tell us Rosario walked downstairs in her Venice home last Thursday and found 26-year-old Vaneza Ines Vasquez lying unresponsive. Paramedics rushed to the scene and transported Vaneza, but ultimately they could not resuscitate her.

We're told Vaneza -- who worked for Rosario -- had recently been suffering migraines and also had hypertension. We're told early autopsy results point to her dying from natural causes.

Toxicology results are still pending, but our sources tell us Vaneza had no history of substance abuse.