Mirna Gonzalez had just stepped away from Gate C7 at Portland (Oregon) International Airport when she heard the screaming. She had left for only a moment to buy a coffee while she and her children waited for an Alaska Airlines flight to Texas just before Christmas, on Dec. 18, 2017. Her 5-year-old daughter, Gabriella, was supposed to be sitting at the gate with her older brother. But when Gonzalez returned, Gabriella's face was covered in blood.