Afeni Shakur, a civil rights activist and former Black Panther whose tumultuous but close relationship with her son, the rapper Tupac Shakur, was the inspiration for much of his work, died on Monday in the San Francisco Bay Area. She was 69.

The sheriff’s office in Marin County, Calif., confirmed the death and said the coroner’s office would seek to determine the cause.

Ms. Shakur was pronounced dead around 10:30 p.m., about an hour after deputies responded to reports of a cardiac arrest at her home in Sausalito and took her to a hospital, the sheriff’s office said on Twitter.

Ms. Shakur had been the driving force behind an effort to continue the legacy of her son, who died at 25 in a drive-by shooting in Las Vegas in 1996. The killing remains unsolved. She established the Tupac Amaru Shakur Foundation in 1997, and shepherded the release of new material through his estate.