The 75-year-old civil rights activist was found dead in the trunk of her car on Friday, about three miles from her home.
SOUNDBITE: DENISE MARCELLE, STATE LAWMAKER, SAYING: "She wanted to show you your history, she wanted you to touch your history, she wanted you to feel your history." Police are investigating her death as a homicide.
Authorities discovered her body after receiving a tip from an anonymous caller who reported a body in the trunk of a vehicle.
Roberts-Joseph was a prominent community leader, in addition to founding the Baton Rouge African-American History Museum in 2001, she also launched a non-profit group to fight drugs and violence.
She organized the city's annual Juneteeth festival commemorating the end of slavery in the U.S. An autopsy is scheduled for Monday to determine the cause and manner of death.