ADA, Okla. -- The search is on for a new district attorney in Ada. Bill Peterson says he's ready to retire.

Peterson's office confirmed that he will retire in January of next year. He's been district attorney for Pontotoc, Seminole, and Hughes County for 27 years.

Many of the cases Peterson has prosecuted over the years have received attention from well known authors such as Robert Mayers and John Grisham.

Peterson will have to submit a letter of resignation to Governor Brad Henry's Office. Governor Henry will then have to appoint a new district attorney to serve out the rest of Peterson’s term.