DALLAS (AP) — Dallas Police Chief David Brown says he’s retiring because, “it’s time to go,” but he’s not saying what he’ll do next.

Brown became the face of a city reeling from tragedy after a sniper killed five law enforcement officers during a July 7 protest against police brutality. He spoke publicly for the first time Thursday about his decision to end his 33 years with the department and six years as chief on October 22.

Brown’s tenure as chief has been marked by tumultuous relationships with police unions, with several calling for his replacement earlier this year. It was also marked by tragedy in 2010, a few weeks after he started the job, when his son was killed in a shootout with police that also left one officer dead.