The U.S. Supreme Court has turned to Quinn Emanuel Urquhart & Sullivan partner Christopher Michel to defend an Oklahoma murder conviction—and death sentence—that the state’s own attorney general argues was tainted by prosecutorial misconduct.

The high court on Friday announced Michel’s appointment as “amicus curiae,” Latin for “friend of the court,” to brief and argue for the state in Glossip v. Oklahoma. The case involves claims by condemned murdered Richard Glossip—who has spent the last quarter century on death row— that prosecutors withheld crucial evidence about the reliability of their star witness.