Louisiana police are searching for the killer of beloved civil rights activist Sadie Roberts-Joseph, whose body was found in the trunk of a car. 

The 75-year-old founder of Baton Rouge's African American museum was last seen Friday at her sister's house, where she went to bake a pan of corn bread after her oven went out. Roberts-Joseph lived three doors down from her sibling. 

Her remains were found about three miles from her house that same day. Her relatives said Roberts-Joseph was at her sister's around 11 a.m. Police located her body at 3:34 p.m.

"Frankly, at this point, it's not even quite real to me," her daughter Angela Machen told The Advocate. "I just cannot quite wrap my thought processes around this being the truth. It's almost unimaginable."

An autopsy conducted Monday ruled her cause of death was "traumatic asphyxia, including suffocation," according to a statement from the coroner's office.

Baton Rouge Police Department spokesman Sgt. Don Coppola told InsideEdition.com. that because of the ongoing investigation, no further details were being released, including who owned the car containing her body.

Meanwhile, tributes poured in for the well-known community leader who worked with law enforcement on programs tackling drug use and gang violence. 

"Ms. Sadie was a tireless advocate of peace," the police department said in a statement. "Our detectives are working diligently to bring the person or persons responsible for the heinous act to justice."

Roberts-Joseph was the curator of the African American museum and had recently organized its annual Juneteenth festival celebrating the date of June 19, 1865, when those enslaved in Texas were finally freed.

"My heart is empty," state Rep. C. Denise Marcelle posted on Facebook. "She never bothered anyone, just wanted to expand her African American museum downtown. Lover working with her and am saddened by her death. Whoever knows what happened to her, please contact the authorities and say something."

"Everyone works hard on every case we have, but when you have a case like this, everybody just has a sense of, all right, let's get together," said East Baton Rouge Parish District Attorney Hillar Moore III. "Everyone's volunteering."

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