EXPLAINER: Social media and the Texas shooter's messages

Could Facebook have known about ominous direct-message threats made by a gunman who Texas authorities say massacred 19 children and two teachers at an elementary school? Could it have warned the authorities?

Texas school shooting: What we know about the victims in Uvalde

Police have not formally identified the victims from the mass shooting at a Uvalde, Texas elementary school, but some family members are sharing pictures. Here's what we know so far about the 19 children and two teachers who were killed.