(Reuters) - A Louisiana civil rights activist and founder of an African-American museum was killed by “traumatic asphyxia” before her body was found in the trunk of her car in the state capital last week, according to a coroner’s report released on Monday.

The Baton Rouge Police Department found the remains of Sadie Roberts-Joseph on Friday afternoon after being tipped off by an anonymous caller. She had seen relatives earlier in the day before her body was found a few miles from her home.

The East Baton Rouge Parish Coroner’s Office ruled her death a homicide caused by “traumatic asphyxia, including suffocation,” a preliminary summary of the autopsy said.

It did not give any other details of her death.

Police have said they are looking for suspects in the killing.

Roberts-Joseph, 75, founded the Odell S. Williams Now & Then African American Museum, which opened in 2001, and a non-profit group called Community Against Drugs and Violence.