An unidentified student let the suspected gunman into Wilmer-Hutchins High School through an "unsecured door," according to arrest records. The 17-year-old suspect then "displayed a firearm and began firing at the students indiscriminately," the affidavit said. Five students were injured in Tuesday's shooting.

Students and parents at a Dallas-area high school have been subjected to a second school shooting in just over a year, despite increased safety protocols.