Mark Woodworth was charged with the fatal shooting of Catherine Roberston and wounding her husband in 1990. Woodworth was 16 years old at the time of Robertson's death.
Due to the prosecutors failure to share important evidence, the state's high court ruled Woodworth's release unless prosecutors decide to retry him.
A spokeswoman said Attorney general Chris Koster intends to retry Woodworth's conviction.(Information contributed from AP news wires)