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Detroit police Chief Ralph Godbee has stepped down after an internal affairs officer revealed that she and the chief had been conducting a sexual relationship, the mayor announced Monday.

Mayor Dave Bing said the 44-year-old Godbee submitted a letter of retirement, effective immediately, from the job he's held since 2010.

Bing said Godbee told him about his decision to retire during a meeting Sunday. The mayor said he did not force Godbee to leave but believes "this was the right decision by the chief." Bing said Godbee was "contrite" and "embarrassed."

"Yes, he did apologize ... he felt he let the citizens of Detroit down," Bing said.

Godbee has not publicly commented on the revelations of his affair with Angelica Robinson. Bing placed Godbee on a 30-day suspension last week pending an investigation into the claims by Robinson's attorney that the 37-year-old woman wanted the relationship to end and Godbee did not.

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At the news conference, Bing said assistant Chief Chester Logan will serve as interim chief. Logan had assumed Godbee's responsibilities during the suspension. Bing said a national search for a new chief for the department is planned.

Angelica Robinson's lawyer revealed that she and Godbee had been seeing each other for about a year, but Godbee was upset when she wanted to end the relationship.

Angelica Robinson posted a photo of herself with her service weapon in her mouth on the social media site Twitter after learning Godbee was at a weekend police conference with another woman, attorney David Robinson has said.

He said Godbee had other officers locate Angelica Robinson and put her under surveillance.

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