Gov. Rick Snyder and Treasurer Andy Dillon have been subpoenaed to give depositions about decisions they made that may be tied to Detroit's bankruptcy filing.
Documents filed Wednesday in Detroit federal court show Snyder's transformation manager Richard Baird also was served a subpoena Friday.
Snyder is ordered to appear Sept. 17 at the American Federation of State, County and Municipal Employees Council 25 office in Detroit. Dillon and Baird must appear Sept. 18.
The union claims state-appointed emergency manager Kevyn Orr has negotiated in bad faith while trying to restructure $18 billion or more in debt.
A hearing is scheduled Tuesday on the state's motion to keep the officials from testifying.
Orr filed for bankruptcy on July 18, making Detroit the largest U.S. city to do so.