Detroit Mayor Dave Bing said Monday that the city's police chief has stepped down from his post after an investigation showed that he had been in a relationship with a subordinate.

"After a 25-year career with the Detroit Police Department, Chief (Ralph) Godbee has submitted a letter announcing his retirement, effective immediately," Bing told reporters.

Godbee had been on a 30-day suspension during the probe.

"There was no need to fire him," Bing said.

Interim Chief Chester Logan, a 38-year veteran, with continue to perform the duties of police chief, he added.