Episode 235

Alex Perez reports from Minneapolis, where a gunman outside a Catholic school church's stained glass windows opened fire on students attending mass – killing an 8-year-old and 10-year-old and injuring dozens more – and Pierre Thomas has the latest on the disturbing details investigators have now learned about the shooter; Rachel Scott has details on the newly installed director of the Centers for Disease Control and Prevention, Susan Monarez, who has been ousted just weeks after being confirmed by the Senate; Victor Oquendo has the latest on the controversial Florida immigration detention center known as "Alligator Alcatraz" that will likely be empty within days, according to an email obtained by ABC News; and more on tonight's broadcast of World News Tonight with David Muir.