A US congressman has asked the FBI to look into law enforcement’s response to the Uvalde, Texas, massacre that killed 19 children and two teachers earlier this week.

Rep. Joaquin Castro, D-Texas, wrote a letter to FBI Director Christopher Wray citing conflicting police reports about the shooting’s timeline and officers’ interactions with the shooter.

The Texas State Police have begun an investigation into law enforcement’s response to the shooting.

Witnesses and neighbors have disputed officials’ accounts of what happened, and law enforcement officials have revised parts of their accounts. As complaints surfaced about a delay in taking action and entering the school, officials sought to reassure the public that they responded immediately to the shooting. “Whether the school security officer and the gunman exchanged fire outside the school,” Castro said, and “how long law enforcement officers were in adjoining classrooms while the gunman barricaded himself in a classroom with students and teachers.”

A 10-year-old girl has been released from University Hospital in San Antonio, the first of three children who were being treated at the San Antonio facility following Tuesday’s attack on Robb Elementary School.

According to the hospital, a 10-year-old girl in critical condition and a 9-year-old girl in good condition are still being treated.

The shooter’s 66-year-old grandmother, who was shot in the face before the gunman drove her pickup to the school, is also in critical condition.

According to a USA TODAY analysis, the shooting deaths of 19 students and two teachers at Robb Elementary School in Uvalde, Texas, added to a growing wave of gun deaths and violence affecting American children.

More people have died in school shootings in the last five years than in the previous 12 years combined, including the Uvalde shooting, the second-deadliest elementary school shooting in U.S. history. According to a database of mass murders maintained by USA TODAY, the Associated Press, and Northeastern University. A mass killing is defined as an incident in which four or more people, not including the perpetrator, are killed.

Families and community members gathered Thursday to mourn the 19 children and two teachers killed in Tuesday’s massacre at Robb Elementary School, as more of the victims’ identities became known.

Crosses with the names of the slain students and teachers were erected in a park in Uvalde.

Irma Garcia and Eva Mireles, the two teachers killed, co-taught their fourth graders and were hailed as heroes for protecting students. Garcia’s husband, Joe Garcia, laid flowers at his wife’s memorial site before passing away unexpectedly later Thursday, leaving their four children to plan two funerals.

Among those killed was 10-year-old Xavier Javier Lopez, who loved to crack jokes and dance cumbia with his family, according to his mother, Felicha Martinez. Layla Salazar, 10, was a fast runner who won ribbons at the school’s field day and sang along to Guns N’ Roses’ “Sweet Child O’ Mine” on the way to school every morning, according to her father, Vincent Salazar.

Jayce Luevanos, 10, awoke every morning and made his grandparents a cup of coffee, according to his grandfather, Carmelo Quiroz. Quiroz stated that he was content and loved. “He was our child.”

The National Rifle Association’s annual convention begins Friday in Houston, and leaders of the powerful gun-rights lobbying group are preparing to “reflect on” – and deflect any blame for – the deadly shooting in Uvalde earlier this week.

Former President Donald Trump and other prominent Republicans are scheduled to speak at the three-day firearms marketing and advocacy event, which is expected to draw anti-gun violence protesters.

Texas Gov. Greg Abbott canceled his appearance at the convention and will instead be in Uvalde to discuss state resources for victims of the mass shooting. Abbott will appear at the conference via video recording, according to his spokeswoman Renae Eze. After “prayerful consideration and discussion with NRA officials,” Lt. Gov. Dan Patrick also decided to cancel his appearance.