The Broward County sheriff on Wednesday defended his office’s response to one of the deadliest school shootings in American history amid questions over whether some of his deputies hung back instead of pursuing the gunman accused of killing 17 people.

Sheriff Scott Israel said that, to his knowledge, deputies followed protocol and did not wait for specialized teams to arrive before going into Marjory Stoneman Douglas High School in Parkland, Fla. But he said that details over the office’s response remained unclear.

“That’s exactly what we’re examining,” Sheriff Israel said, noting that active shooter protocols require confronting suspects as quickly as possible. “You don’t wait for SWAT, you get in, and you push toward the shooter.”