ALBANY, N.Y. — New York Comptroller Thomas DiNapoli plans to audit the branch of Attorney General Andrew Cuomo’s office that acts as collection bureau for the state.

The Civil Recoveries Bureau sues to recover debts to New York, like unpaid state university tuition and payments for mental health treatment. The comptroller’s office says a letter about the audit was sent last week, part of a process of checking revenue streams from various agencies.

Cuomo is engaged in a broad investigation of the comptroller’s office and management of the $126 billion state retirement fund. Focusing on DiNapoli’s predecessor, Alan Hevesi, it has resulted in charges against some former officials.

Cuomo spokesman John Milgrim says Thursday the attorney general’s office is reviewing the comptroller’s letter.