A jury in May
acquitted Shelby of manslaughter
in the killing of Terence Crutcher last year.
Crutcher was unarmed, but Shelby said she thought he was reaching into his vehicle for a weapon.
Attorney Shannon McMurray said Shelby has submitted a resignation letter to the department, effective Aug. 3,
CBS News
reports.
Crutcher's family filed a wrongful death lawsuit in federal court in June against Shelby and the city of Tulsa. The suit seeks at least $75,000 in damages and calls for widespread reform in the Tulsa police department, including mandatory training for officers on managing suspects with mental health or substance abuse issues.