The gunman who massacred 19 children and two teachers at an elementary school in Texas had warned in online messages minutes before the attack that he had shot his grandmother and was going to shoot up a school, the governor said Wednesday.

Salvador Ramos, 18, used an AR-15-style semi-automatic rifle in the bloodbath Tuesday at Robb Elementary School in Uvalde. He had legally bought two such rifles just days before, soon after his birthday, authorities said.

Investigators shed no immediate light on the motive. Gov. Greg Abbott said Ramos, a resident of the community about 85 miles (135 kilometers) west of San Antonio, had no known criminal or mental health history.

But about 30 minutes before the bloodbath, Ramos made three social media posts, Abbott said. According to the governor, Ramos posted that he was going to shoot his grandmother, then that he had shot the woman, and finally that he was going to shoot up an elementary school.

Seventeen people were also injured in the attack.

“Evil swept across Uvalde yesterday. Anyone who shoots his grandmother in the face has to have evil in his heart,” Abbott said at a news conference. “But it is far more evil for someone to gun down little kids. It is intolerable and it is unacceptable for us to have in the state anybody who would kill little kids in our schools.”

Democrat Beto O’Rourke, who is running against Abbott for governor this year, interrupted the news conference, calling the Republican’s response to the tragedy “predictable.” O’Rourke was escorted out while members of the crowd yelled at him, with one man calling him a “sick son of a bitch.”

As details of the latest mass killing to rock the U.S. emerged, grief engulfed the small town of Uvalde, population 16,000.

The dead included an outgoing 10-year-old, Eliahna Garcia, who loved to sing, dance and play basketball; a fellow fourth grader, Xavier Javier Lopez, who had been eagerly awaiting a summer of swimming; and a teacher, Eva Mireles, with 17 years’ experience whose husband is an officer with the school district’s police department.

“I just don’t know how people can sell that type of a gun to a kid 18 years old,” Eliahna’s aunt, Siria Arizmendi, said angrily through tears. “What is he going to use it for but for that purpose?”

Lt. Christopher Olivarez of the Texas Department of Public Safety told CNN that all of those killed were in the same fourth-grade classroom.

The killer “barricaded himself by locking the door and just started shooting children and teachers that were inside that classroom,” Olivarez said. “It just shows you the complete evil of the shooter.”

Law enforcement officers eventually broke into the classroom and killed the gunman. Police and others responding to the attack also went around breaking windows at the school to enable students and teachers to escape.

The attack in the predominantly Latino town of Uvalde was the deadliest school shooting in the U.S. since a gunman killed 20 children and six adults at Sandy Hook Elementary in Newtown, Connecticut, in December 2012.

The bloodshed was the latest in a seemingly unending string of mass killings at churches, schools, stores and other sites in the United States. Just 10 days earlier, 10 Black people were shot to death in a racist rampage at a Buffalo, New York, supermarket.

In a somber address to the nation hours after the attack in Texas, President Joe Biden pleaded for Americans to “stand up to the gun lobby” and enact tougher restrictions, saying: “When in God’s name are we going to do what has to be done?”

But the prospects for any reform of the nation’s gun regulations appeared dim. Repeated attempts over the years to expand background checks and enact other curbs have run into Republican opposition in Congress.

On social media in the days and hours before the massacre, Ramos appeared to drop hints that something was going to happen.

On the day Ramos bought his second weapon last week, an Instagram account that investigators say apparently belong to Ramos carried a photo of two AR-style rifles. Ramos apparently tagged another Instagram user, one with more than 10,000 followers, asking her to share the picture with her followers.

“I barely know you and u tag me in a picture with some guns,” replied the Instagram user, who has since removed her profile. “It’s just scary.”

On the morning of the attack, the account linked to the gunman replied: “I’m about to.”

Instagram confirmed to The Associated Press that it is working with law enforcement to review the account but declined to answer questions about the postings. Investigators are also looking at an account on TikTok, possibly belonging to the shooter, with a profile that reads: “Kids be scared IRL,” an acronym meaning “in real life.” The profile is not dated.

Investigators do not yet know why Ramos targeted the school, said Steve McCraw, director of the Texas Department of Public Safety.

“We don’t see a motive or catalyst right now,” he said.

Officers found one of the rifles in Ramos’ truck, the other in the school, according to the briefing given to lawmakers. Ramos was wearing a tactical vest, but it had no hardened body-armor plates inside, lawmakers were told. He also dropped a backpack containing several magazines full of ammunition near the school entrance.

One of the guns was purchased at a federally licensed dealer in the Uvalde area on May 17, according to state Sen. John Whitmire, who was briefed by investigators. Ramos bought 375 rounds of ammunition the next day, then purchased the second rifle last Friday.

On Tuesday morning, Ramos shot and wounded his grandmother at her home, then left. Neighbors called police when she staggered outside and they saw she had been shot in the face, Department of Public Safety spokesperson Travis Considine said.

Ramos then crashed his truck through a railing on the school grounds, and an Uvalde school district officer exchanged fire with him and was wounded, Considine said. Ramos went inside and exchanged more gunfire with two arriving Uvalde police officers, who were still outside, Considine said. Those officers were also wounded.

Dillon Silva, whose nephew was in a nearby classroom, said students were watching the Disney movie “Moana” when they heard several loud pops and a bullet shattered a window. Moments later, their teacher saw the attacker stride past the door.

“Oh, my God, he has a gun!” the teacher shouted twice, according to Silva. “The teacher didn’t even have time to lock the door,” he said.

A tactical team forced its way into the classroom where the attacker was holed up and was met with gunfire from Ramos but shot and killed him, according to Olivarez.

In the aftermath, families in Uvalde waited hours for word on their children. At the town civic center where some gathered Tuesday night, the silence was broken repeatedly by screams and wails. “No! Please, no!” one man yelled as he embraced another man. On Wednesday morning, volunteers were seen arriving with Bibles and therapy dogs.

Three children and an adult were being treated at a San Antonio hospital, where two of them — a 66-year-old woman and 10-year-old girl — were listed in serious condition.

Uvalde, home to about 16,000 people, is about 75 miles from the Mexican border. Robb Elementary, which has nearly 600 students in second, third and fourth grades, is a single-story brick structure in a mostly residential neighborhood of modest homes.

The close-knit community, built around a shaded central square, includes many Hispanic families who have lived there for generations. It sits amid fields of cabbage, onions, carrots and other vegetables. But many of the steadiest jobs are supplied by companies that produce construction materials.

The attack came as the school was counting down to the last days of the school year with a series of themed days. Tuesday was to be “Footloose and Fancy,” with students wearing nice outfits.

Texas, which has some of the most gun-friendly laws in the nation, has been the site of some of the deadliest shootings in the U.S. over the past five years.

In 2018, a gunman killed 10 people at Santa Fe High School in the Houston area. A year before that, a gunman shot more than two dozen people to death during a Sunday service in the small town of Sutherland Springs. In 2019, a gunman at a Walmart in El Paso killed 23 people in a racist attack targeting Hispanics.

The shooting came days before the National Rifle Association annual convention was set to begin in Houston. The governor and both of Texas’ U.S. senators, all of them Republicans, were among the scheduled speakers at a forum Friday.