Texas elementary school shooting: What do we know so far?

Many questions remain to be answered about the elementary school shooting in Uvalde, Texas

A gunman stormed into an elementary school Tuesday in Uvalde, Texas, killing 19 children and two teachers in the United States' deadliest school shooting in nearly a decade. Law enforcement officers killed the shooter, identified as a local 18-year-old who had shot and wounded his grandmother shortly before the massacre at Robb Elementary. Investigators haven't disclosed any motives for the shootings.

A look at what we know so far:

WHAT HAPPENED IN UVALDE?

The attacker crashed his truck outside the school and made his way into a fourth-grade classroom, state police said. After locking the classroom door, he opened fire around 11:30 a.m. with an AR-15-style rifle, carrying multiple magazines.

Law enforcement officers ultimately forced their way into the classroom and shot Ramos to death after he fired at them, police said.

Other officers and responders shattered some of the school's windows so teachers and students could escape.

Ramos was wearing a tactical vest, though not body armor, according to state senators who said they were briefed on the shooting. There was another AR-15-style rifle in his truck, and a backpack with several magazines full of ammunition was found in near the school entrance.

WHO WERE THE VICTIMS?

Authorities haven't yet released the victims' names, but some information about them has emerged from their families.

Uziyah Garcia was only 8 and “the sweetest little boy that I’ve ever known," said grandfather Manny Renfro, recalling how the youngster was already able to master football pass patterns.

With the school year coming to a close, Xavier Javier Lopez, 10, had been looking forward to a summer of swimming, cousin Lisa Garza said. Ebullient and loving, he was "just enjoying life, not knowing that this tragedy was going to happen today,” she said.

Eva Mireles, 44, had been teaching for 17 years, according to a welcome letter to students she wrote last fall. She and her husband, a school police officer, had a grown daughter.

Mireles wrote that she loved running and hiking, and relative Amber Ybarra said she had an adventurous spirit.

WHO WAS THE GUNMAN?

Authorities identified the shooter as Salvador Ramos, 18. He lived in Uvalde itself, a predominantly Latino city of about 16,000 people in a farming area roughly 75 miles (120 kilometers) from the Mexican border and 85 miles (135 kilometers) from San Antonio.

Investigators have been scrutinizing an Instagram account that apparently belonged to him. In the days before the shooting, posts featured a photo of a hand holding an ammunition magazine and another photo of two AR-15-style rifles. The account asked another Instagram user to share the latter photo with her 10,000 followers; she declined, saying it was “scary” and she barely knew him.

On the morning of the massacre, the account linked to Ramos sent her an ominous message: “I'm about to.”

That morning, Ramos shot and wounded his grandmother at her Uvalde home, which is also the address he used on his driver's license and gun paperwork, according to a law enforcement briefing provided to a state senator.

Instagram declined to answer questions about the postings and said it is working with law enforcement to review the account.

WHERE DID THE GUN COME FROM?

The gunman legally bought his weapons soon after his 18th birthday and days before the attack, law enforcement officials told state lawmakers.

He purchased one rifle from a federally licensed gun dealer in the Uvalde area on May 17, according to a state police briefing to state Sen. John Whitmire. On May 18, the gunman bought 375 rounds of ammunition. Then, two days later, he bought a second rifle.

WHAT DON'T WE KNOW?

Authorities haven't disclosed a full list of the victims. Nor have many important details about the attack been made public.

Among them: the time of the shooting of Ramos' grandmother and when authorities were alerted to it; when and how school officers or law enforcement spotted or engaged with him as he approached the school; how many people may have seen the social media posts attributed to him; and what, if any, history he had with Robb Elementary.

There are "a lot of unanswered questions, and we’re trying to make a determination of what triggered this, what caused this 18-year old to commit such a heinous act, this mass shooting here in this small, tight-knit community,” Texas Department of Public Safety Lt. Christopher Olivarez said on NBC’s “Today” show.