(BATON ROUGE, La.) — A beloved 75-year-old community activist in Louisiana whose body was discovered in the trunk of her car died from “traumatic asphyxia, including suffocation,” according to an autopsy.Sadie Roberts-Joseph, who teamed up with police on an anti-drug and violence program, was found slain Friday afternoon when police were directed to her car parked in a residential neighborhood northeast of downtown Baton Rouge, police said.”It is with great sadness and respect to investigate any unexpected or traumatic death. When our investigation involved an innocent victim, such as Ms. Sadie Joseph, it is particularly tragic,” Dr. William “Beau” Clark, the East Baton Rouge Parish Coroner, said in a statement.Police have yet to identify a suspect in Roberts-Joseph’s homicide but said investigators are working around the clock to solve the case.”She’s special. She’s touched so many people in this community over the years. She was a true public servant,” Baton Rouge Police Chief Murphy Paul told ABC News.Roberts-Joseph was last seen alive visiting her sister about 11 a.m. on Friday. Her body was discovered in her car a little over three miles from her home about 3:45 p.m. on Friday, police and relatives said.”We do know the time when she was last seen and the time, obviously, when the body was discovered. We’re working on that time frame and we’re focusing in on what happened between that time,” Paul said.The slaying of Roberts-Joseph, who was well known in Baton Rouge, came as a complete shock for her family and the community.”We’re devastated that someone has actually killed her and put her in the trunk of her own car,” Roberts-Joseph’s niece, Pat McCallister-Leduff, told ABC News.The victim’s sister, Beatrice Johnson, told The Advocate newspaper of Baton Rouge that Roberts-Johnson stopped by her house around 11 a.m. on Friday. She said her sister lived near her in the Scotlandville neighborhood of Baton Rouge and would check in with her daily.”Friday, she came by [because] she had mixed some cornbread, but her oven went out, and she brought it here to put in the oven,” Johnson told the newspaper. “The bread is still there. She never came back to get it.”Roberts-Joseph helped found the Odell S. Williams Now and Then African-American History Museum in 2001. The museum, now known as the Baton Rouge African-American History Museum, is housed on the campus of New St. Luke Baptist Church in Baton Rouge.She also organized the city’s annual Juneteenth festival at the museum, commemorating the abolition of slavery in the U.S., and partnered with Baton Rouge police to launch a Community Against Drugs and Violence program.In a recent interview with ABC affiliate station WBRZ-TV in Baton Rouge, Roberts-Joseph said her work at the museum and the annual Juneteenth event was meant “to celebrate, to embrace” African American history and to “learn of our past and to be able to move forward in unity.”Baton Rouge police are asking anyone with information on the case to contact homicide detectives immediately.”I have no idea why someone would do such a heinous act or commit such a heinous act for someone who had nothing but love for this community and love for people,” Baton Rouge Mayor Sharon Weston Broome told ABC News.Copyright © 2019, ABC Radio. All rights reserved.