On Tuesday, May 24 a gunman stormed into an elementary school 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 and spelled out his violent plans in online messages shortly before the massacre at Robb Elementary. Investigators say they don't yet know a motive for the shootings, reports AP.

What happened in Uvalde?

The attacker shot his 66-year-old grandmother in the face at their Uvalde home, then fled in her truck as she summoned help, according to Gov. Greg Abbott, Texas Public Safety Director Steve McCraw and other officials.

A short distance away, Ramos crashed the truck outside the school, got out with a rifle and approached a back door, officials said. They said an officer assigned to the school "engaged" Ramos, but the gunman got into the building and down a hallway to a fourth-grade classroom. After locking the classroom door, he opened fire around 11:30 a.m. with an AR-15-style rifle, carrying multiple magazines. A team including local officers and Border Patrol agents ultimately forced the door open 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 armour, 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 near the school entrance.

Who did he kill?

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

Eliahna Garcia was an outgoing 10-year-old who loved to sing, dance, play sports and be with her family, according to aunt Siria Arizmendi. 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.

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

Swift-footed Layla Salazar, 10, had won six races at the school's field day.

"She was just a whole lot of fun," said her father, Vincent Salazar, remembering how she danced to TikTok videos and sang along with him to the Guns N' Roses song "Sweet Child O' Mine" every morning on the way to school.

Jailah Nicole Silguero, 10, hadn't wanted to go to school Tuesday, appearing to think that something bad would happen, her mom, Veronica Luevanos, told Univision. A cousin of Jailah's also was killed.

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.

Profile of a Killer

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 kilometres) from the Mexican border and 85 miles (135 kilometres) from San Antonio.

A high school dropout, Ramos had no known criminal record or history of mental health problems, Abbott said.

In the half-hour before the school killings, Ramos used Facebook to say that he was going to shoot his grandmother, then that he had done so, and then that he was going to shoot up an elementary school, without specifying which one, officials said.

Facebook said Ramos' posts were private messages that came to light after the killings.

Investigators also have been scrutinising an Instagram account that apparently belonged to Ramos. 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."

Instagram declined to answer questions about the postings.

It was legal

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 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.

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

Among them: what transpired between Ramos and the school officer who first encountered him; who saw the online posts attributed to him; what, if any, history he had with Robb Elementary; and why he went on the rampage.

"We don't see a motive or catalyst right now," McCraw said Wednesday (May 25) afternoon.

Police role under scanner

"Go in there! Go in there!" nearby women shouted at the officers soon after the attack began, said Juan Carranza, 24, who saw the scene from outside his house, across the street from Robb Elementary School in the close-knit town of Uvalde. Carranza said the officers did not go in.

Javier Cazares, whose fourth grade daughter, Jacklyn Cazares, was killed in the attack, said he raced to the school when he heard about the shooting, arriving while police were still gathered outside the building.

Upset that police were not moving in, he raised the idea of charging into the school with several other bystanders.

"Let's just rush in because the cops aren't doing anything like they are supposed to," he said. "More could have been done."

"They were unprepared," he added.

Minutes earlier, Carranza had watched as Salvador Ramos crashed his truck into a ditch outside the school, grabbed his AR-15-style semi-automatic rifle and shot at two people outside a nearby funeral home who ran away uninjured.

Officials say he "encountered" a school district security officer outside the school, though there were conflicting reports from authorities on whether the men exchanged gunfire. After running inside, he fired on two arriving Uvalde police officers who were outside the building, said Texas Department of Public Safety spokesperson Travis Considine. The police officers were injured.

After entering the school, Ramos charged into one classroom and began to kill.

He "barricaded himself by locking the door and just started shooting children and teachers that were inside that classroom," Lt. Christopher Olivarez of the Department of Public Safety told CNN. "It just shows you the complete evil of the shooter."

All those killed were in the same classroom, he said.