Uvalde shooting timeline reflects time gunman spent in classroom

A Texas law enforcement official says the 18-year-old gunman who slaughtered 21 people at an elementary school entered the building "unobstructed" through a door that was apparently unlocked.

A fourth-grade teacher and kids who were "loving" and "full of life" were among those killed in a mass shooting at a Texas elementary school Tuesday.

This photo shows 18-year-old Salvador Ramos, identified by law enforcement sources as the Robb Elementary School shooting suspect.

Video shows parents begging police officers to charge into the Texas elementary school where a gunman's rampage killed 19 children and two teachers.

There was blood in the hallway and children were covered in it, a student who survived the elementary school shooting in Uvalde, Texas, told ABC News.

Law enforcement says the United States has seen a sharp rise in deadly mass shootings.