Mississippi ? Federal authorities will continue to investigate the 1964 Mississippi killings of three civil rights workers — a case that helped pass landmark legislation — despite the death of a key suspect, the Justice Department says.

Billy Wayne Posey, 73, died Thursday. Federal investigators were looking into his possible involvement in the June 21, 1964, killings of James Chaney, Andrew Goodman and Michael Schwerner, who had been working to register black voters.

Posey’s funeral was Saturday in Philadelphia, Miss., the town at the heart of the case.

On Friday afternoon, Alejandro Miyar, a spokesman for the Justice Department, said the death does not “alter our cold-case investigation.” He said federal authorities are assisting state investigators who could bring state charges.