Authorities announced on Tuesday that a former tenant of the founder of an African American history museum in Louisiana was charged with her murder.

Baton Rouge police announced that Ronn Jermaine Bell, 38, was arrested for allegedly killing Sadie Roberts-Joseph, who was found dead in the trunk of her car on Friday. He was charged with first degree murder. A preliminary autopsy conducted by the East Baton Rouge Parish Coroner’s Office showed Roberts-Joseph, 75, died of traumatic asphyxia. Bell was a tenant in one of Roberts-Joseph’s rental houses.  Police said they did not have a motive yet in the case, only that he was several months behind on his rent. He is a registered sex offender who pleaded guilty in 2007 to the aggravated rape of an 8-year-old girl and served seven years in prison.

Roberts-Joseph founded the Odell S. Williams Now and Then African American History Museum, now known as the Baton Rouge African American History Museum, in 2001. The museum features exhibits on African art, growing cotton, black inventors and a 1953 bus from the period of civil rights boycotts in Baton Rouge, among others.

Man charged in murder of activist Sadie Roberts-Joseph, 75, found dead in a car’s trunk