The brothers of James Earl Ray should be investigated to determine whether they had any role in Martin Luther King Jr.'s assassination, a Tennessee prosecutor says.

Shelby County prosecutor Bill Gibbons urged the Justice Department to investigate brothers Jerry Ray, 63, and John Ray, 65, as part of the agency's renewed probe into the slaying."I strongly urge the Justice Department to take a close look at the activities of James Earl Ray's brothers and their possible involvement in this tragedy," Gibbons said in a Sept. 3 letter obtained by The Commercial Appeal newspaper.

Both men have denied involvement in the 1968 slaying of the civil rights leader. James Earl Ray, who was sentenced to 99 years in prison, pleaded guilty but later recanted and unsuccessfully sought a trial.

He died of liver disease in April.