For 17 years, Sherwood Brown has claimed it was not he but an accomplice who sexually assaulted a 13-year-old girl.
Prosecutors used that evidence to seek a death sentence at Brown's 1995 trial in DeSoto County.
Now the Mississippi Supreme Court has unanimously decided to give Brown his chance to prove his innocence.
The justices gave Brown 30 days to file a motion in DeSoto County Circuit Court and for that court to determine if any biological evidence exists. If the evidence exists, the Supreme Court says the judge will order DNA testing.
Brown was convicted in the 1993 deaths of 82-year-old Betty Boyd and her 49-year-old daughter-in-law, Verline Boyd. He also was convicted in the killing of 13-year-old Evangelo Charmain Boyd, the daughter of Verline and granddaughter of Betty.