The older brother of Atlanta Mayor Kasim Reed kept his city job and kept driving around town, sometimes in a city-owned vehicle, after his license was suspended and he was detained in May for driving on a suspended license. That incident was not a secret in the mayor’s office.

That ended Friday morning, when Tracy F. Reed resigned after the city’s human resources and law departments launched separate investigations.

At a news conference Friday, the mayor confirmed that his brother had violated city policy. Tracy Reed had worked for the city for 12 years and was recently made a supervisor in the Office of Contract Compliance.

“This morning, my brother submitted a formal letter of resignation to his supervisor,” Kasim Reed said at the news conference at City Hall. “He loved working for the city and he loved helping small and disadvantaged businesses.

“He told me he realized he displayed a lapse in judgment,” the mayor continued. “The last 72 hours have been very difficult for me. I never hesitate to say that I love my big brother. However, as mayor of the city, I have pledged to hold employees accountable.”

More details came to light Friday afternoon. An incident report obtained by The Atlanta Journal-Constitution through an open records request revealed that Tracy Reed was stopped May 4 on Campbellton Road near southwest Atlanta while driving another person’s black Chevrolet Suburban.

A police officer running what was described as a random vehicle registration check found that the tags were for a Honda Accord.

Reed said he didn’t have his license with him, but the officer ran a search and found that his license had been suspended in January 2006 for failure to appear in court.

In any case, Reed’s license had expired in September 2006, 4 1/2 years before the May 4 stop, according to the police report.

“Mr. Reed also advised me that he is a city of Atlanta employee,” the officer wrote in the report. Reed was taken to the Atlanta Police Department’s Zone 4 Precinct nearby.

The city’s law department is investigating how police handled an Oct. 28 traffic stop in which Tracy Reed was apparently allowed to drive away without a ticket after being stopped while driving with a suspended license. At that time, he also had a bench warrant out for his arrest for failing to appear in court to answer a charge of driving on a suspended license. The arrest warrant was canceled Thursday after Tracy Reed’s court date was reset.

Kasim Reed said Friday was the hardest day he has had since becoming mayor nearly two years ago. He said he learned of the problem Tuesday night from a staff member, and called his brother immediately. But he said he did not tell his brother to resign.

He knew about his brother’s May 4 incident, but was assured that Tracy Reed had been to court and taken care of the problem, said spokeswoman Sonji Jacobs Dade. On Tuesday, it became clear that the issue had not been resolved, she said.

The mayor said the results of the law department and human resources investigations will be made public within days, although neither was completed by Friday afternoon.

Footage of the Oct. 28 stop, which aired Wednesday night on a local TV station, appears to show a zone commander interrupting a traffic stop made by another officer, who had pulled over Tracy Reed for expired tags. The zone commander appeared to allow Reed to drive away without a ticket.

The city, in a letter sent Friday to the station, asked for a “courtesy copy” of the footage — implying that the city no longer has the raw footage. The AJC received the letter in response to an open records request for the video.

The mayor said that his brother had two traffic tickets in 2006, but his failure to appear in court started a series of events that culminated with Friday’s resignation.

“He forgot about the [court] date,” Kasim Reed said. “Went for a long time without being stopped.”

Tracy Reed did not receive preferential treatment by being allowed to resign instead of being fired after the Oct. 28 stop, the mayor said.

“Most employees in the city of Atlanta would not be terminated for this offense,” Kasim Reed said.

Staff writer Steve Visser contributed to this article.