UVALDE, Texas (NewsNation) — Frustrated onlookers urged law enforcement to charge into the Texas elementary school where an 18-year-old opened fire and killed 19 children and two adults Tuesday, a witness told the Associated Press.

Juan Carranza, 24, told the outlet he saw the scene from the outside of his house across the street from Robb Elementary School in Uvalde, Texas. He said he heard women yelling, “Go in there! Go in there!” at officers, but noticed they did not enter the school.

Carranza said he also watched the shooter crash his truck outside the school, grab a rifle and shoot at two people outside a nearby funeral home who ran away uninjured.

Javier Cazares said he rushed to the school when he heard about the shooting and saw police crowded outside the building. He said since the police were not going into the school, he thought of running in with other bystanders.

“Let’s just rush in because the cops aren’t doing anything like they are supposed to,” he told the Associated Press. “More could have been done.”

“They were unprepared,” he added.

His daughter, fourth grader Jacklyn Cazares, died in the attack.

“Initially, there were several officers, local officers, here from Uvalde trying to make entry prior to the tactical team arriving,” Lt. Chris Olivarez explained. “They were met with gunfire. Two officers were shot. They were unable to make entry into the school, and that’s when the gunman barricaded himself inside the classroom. Moments later, that’s when that off-duty tactical officer arrived from Border Patrol, along with a deputy and other tactical officers as well, also local police officers. They made a forcible entry into that classroom and they were met with gunfire as well … That off-duty [agent] was nearly shot in the head by the suspect. By that point, they were able to return fire, shot the suspect. The suspect was deceased on scene.”

Emotions are raw in the tight-knit town after 18-year-old gunman Salvador Ramos opened fire on Robb Elementary School. 19 children and two adults lost their lives, while 17 others received injuries.

Texas Governor Greg Abbott says there were warning signs on social media beginning 30 minutes before the attack in the form of chilling messages.

According to Gov. Abbott, the first message said, “I’m going to shoot my grandmother.” The second, “I shot my grandmother.” The final message, “I’m going to shoot an elementary school.”

Governor Abbott says the streak of violence began when the gunman shot his grandmother in the face. She then alerted police.

From there, officials say the 18-year-old took off and crashed his car near the elementary school. That’s when the massacre started at around 11:30 a.m.

Authorities tell NewsNation Ramos entered a back door of the school, walked two short hallways and barricaded himself in a fourth-grade classroom, indiscriminately killing 19 young students and two adults.

While dark details of the shooting have appeared, incredible stories of heroism have also come to light.

A U.S. Border Patrol Agent ended Ramos’ shooting rampage. The agent was called in for backup and rushed right to the room where the shooting was unfolding, bravely going face to face with the shooter. He shot and killed the gunman. During that exchange, the agent was also shot. He is expected to be OK. Amid the chaos, police officers broke windows around the school in efforts to try to evacuate children and teachers inside.

Some students were taken to a civic center to be reunited with their families while others were transported to local hospitals.

At least 13 wounded children were taken to Uvalde Memorial Hospital. Staff members in scrubs and devastated victims’ relatives families could be seen weeping as they walked out of the medical center.

Uvalde families waited hours for word on their children. Adolfo Cruz, a 69-year-old air conditioning repairman, was still outside the school as the sun set, seeking word on his 10-year-old great-granddaughter, Eliajha Cruz Torres.

He drove to the scene after receiving a terrifying call from his daughter following shortly after the first reports of the shooting. He said other relatives were at the hospital and the civic center.

Waiting, he said, was the heaviest moment of his life.

“I hope she is alive,” Cruz said.

The attack on the elementary school was the latest grim moment for a country scarred by a string of massacres, coming just 10 days after a deadly, racist rampage at a supermarket in Buffalo, New York. Tuesday’s assault in the heavily Latino town of Uvalde was the deadliest shooting at a U.S. school since a gunman killed 20 children and six adults at Sandy Hook Elementary in Newtown, Connecticut, in December 2012. The Uvalde shooting marks the deadliest school shooting in Texas history.

In wake of the tragedy, President Joe Biden says he and the first lady will be visiting Uvalde “in the coming days.”

“Jill and I will be traveling to Texas in the coming days to meet with the families and let them know we have a sense, just a sense, of their pain. And hopefully bring some little comfort to he community in shock, in grief and in trauma. As a nation, I think we all must be there for them,” President Biden said Wednesday.

Hours after the mass shooting, President Biden called for new gun restrictions in an address to the nation.

“As a nation, we have to ask, when in God’s name are we going to stand up to the gun lobby? When in God’s name are we going to do what has to be done?” Biden asked. “Why are we willing to live with this carnage?”

Officials have not discovered a motive for the massacre, but say Ramos acted alone. A neighbor of the 18-year-old said he was known to be bullied by teens and often fought with his grandmother. Governor Abbott said, “reportedly there has been no criminal history identified yet” and “no known mental health history of the gunman.”

Uvalde, home to about 16,000 people, is approximately 75 miles from the border with Mexico. Robb Elementary, which has nearly 600 students in second, third and fourth grades, is in a mostly residential neighborhood of modest homes.

The attack came as the school was counting down to the last days of the school year that has since been called off by the superintendent.

“My heart is broken today,” said Hal Harrell, the school district superintendent. “We’re a small community, and we’re going to need your prayers to get through this.”

A Robb Elementary Memorial Fund account has been opened at First State Bank of Uvalde for the families of Robb Elementary, according to the school district. Donations will be accepted at all FSB branches. Checks should be payable to the “Robb School Memorial Fund” and can be mailed to 200 E. Nopal St. Uvalde, TX 78801. Donations through Zelle can be sent to robbschoolmemorialfund@gmail.com, according to the school district.