The unnamed Senior D.A. was played by Robert D. Raiford in The Rage: Carrie 2.
He is the Senior D.A. of Chamberlain. He accepted a bribe from Lou Stark to cover up the machinations of the football team that lead to Lisa Parker´s suicide out of political interests, since they belonged to the most influential families in town. This contributed to the disaster of the Black Party, which caused the death of so many people.
His fate is unknown, but it wouldn´t come as a surprise, if he would be forced to step down and face trial for his misdeed after what happened.