Timeline of police response to Texas school shooting remains unclear

Emergency officials respond to an active shooter report in Texas.
In this image taken from video emergency personnel and law enforcement officers respond to a high school near Houston after an active shooter was reported on campus, Friday, May 18, 2018, in Santa Fe, Texas. The Santa Fe school district issued an alert Friday morning saying Santa Fe High School has been placed on lockdown.
KTRK-TV ABC13 via AP