David_Brown_crop_jpg_800x1000_q100Robert W. Hart for The Texas Tribune

Flanked by civic and religious leaders, Dallas Police Chief David Brown speaks to a crowd attending the vigil for five slain police officers, victims of a sniper attack, at Dallas’ Thanksgiving Square on July 8, 2016. Photo by Robert W. Hart for The Texas Tribune.

Flanked by civic and religious leaders, Dallas Police Chief David Brown speaks to a crowd attending the vigil for five slain police officers, victims of a sniper attack, at Dallas’ Thanksgiving Square on July 8, 2016. Photo by Robert W. Hart for The Texas Tribune.

Flanked by civic and religious leaders, Dallas Police Chief David Brown speaks to a crowd attending the vigil for five slain police officers, victims of a sniper attack, at Dallas’ Thanksgiving Square on July 8, 2016. Photo by Robert W. Hart for The Texas Tribune.