(TMZ)Tupac's mother, Afeni Shakur, died late Monday night ... possibly from a heart attack.
The Marin County Sheriff's Department says it responded to Afeni's Sausalito, CA home Monday around 9:43 PM for a report of a cardiac arrest. She was transported to a hospital ... where she was pronounced dead at 10:28 PM.
Afeni was a philanthropist, founding and running the Tupac Amaru Shakur Foundation after her son's death. She was also a Black Panther ... and defended herself in court when she was accused of multiple bombings.
As keeper of all things Tupac, Afeni greenlit the biopic, "All Eyez on Me" ... which just recently wrapped filming.
The Marin County Sheriff says the coroner will investigate to determine the exact cause of Afeni's death.
She was 69 years old.