The bright sunshine in Uvalde belies the cloud of anger and anguish enveloping the small Texas city.

Local funeral homes are so overwhelmed, it will take weeks to bury some of the 19 children and two teachers killed Tuesday at Robb Elementary School.

And days after the massacre, victims' families learned more about what really happened in classrooms 111 and 112 during their loved ones' final moments.

Children who were trapped near the gunman called 911 several times, begging for help. But police waited inside the school for about an hour before confronting the shooter.

It's not clear how many of the 19 children or two teachers killed might have been saved had police entered earlier.

"The devastating injuries that many of those kids sustained, there's no doubt some of those children bled to death while waiting for police to make entry," said CNN Law Enforcement Analyst Charles Ramsey, a former Philadelphia police commissioner.

"There's just no question in my mind that probably took place," Ramsey said Sunday. "There's no way you can justify that."

But it's not fair to direct all blame at the school district police chief, who authorities say made the decision to not immediately breach a classroom door, Texas state Sen. Roland Gutierrez, D-San Antonio, said Sunday.

"At the end of the day, everybody failed here," he said. "We failed these children. We even failed them in the Texas Legislature."

It's unclear what changes will happen on the state or federal levels to help curb school shootings and public massacres. The elementary school slaughter in Uvalde marked at least the 30th shooting at a K-12 school in just the first five months of this year.

President Joe Biden visited Uvalde on Sunday to offer his sympathy and support. Just 12 days earlier, Biden visited New York state after a racist massacre at a Buffalo grocery store left 10 people dead.

The suspects in both massacres were 18 years old and had legally purchased their weapons.

The disturbing new timeline

In active shooter situations, all law enforcement officers in Texas are trained to move in and confront the attacker, according to the active shooter guidelines in the state's commission on law enforcement 2020 training manual.

"As first responders we must recognize that innocent life must be defended," the manual says. "A first responder unwilling to place the lives of the innocent above their own safety should consider another career field."

Those guidelines apparently weren't followed in Uvalde.

After days of public clamoring, authorities in Texas released a clearer timeline of how the tragedy unfolded.

Uvalde police officers entered the school about two minutes after the shooter, said Col. Steven McCraw, director of the Texas Department of Public Safety.

But the incident commander at the scene -- the school district's police chief -- believed the situation had transitioned from an active shooter to a "barricaded subject," McCraw said.

It's not clear why the district police chief, Pedro "Pete" Arredondo, may have believed that. Arredondo made the call for officers not to go into the classroom as they waited for the room's key and tactical equipment, officials said.

During a window of about 70 minutes, officers went inside the building and called for more resources, such as equipment and negotiators, McCraw said.

Up to 19 officers were standing in the hallway more than 45 minutes before police entered the classroom.

Eventually, members of a border patrol tactical team arrived at the scene, entered the classroom and killed the gunman, more than an hour after the mass shooting started.

McCraw said the decision to not enter the classroom sooner was the wrong decision, and officers should have confronted the shooter immediately.

Donations of blood, food and funeral services

Since the massacre, graduations and other celebratory events have been canceled as the community mourns the shattering loss of some of its most vulnerable.

Funeral homes in Uvalde have committed to covering costs for families of the 21 victims, with some services beginning Monday.

"We have fought together as a community and we will pull together as one now in our time of need," Hillcrest Memorial Funeral Home wrote on its Facebook page.

The Rushing-Estes-Knowles Mortuary echoed support for the Uvalde community: "Today, our resolve is stronger than ever. We are here for the people of Uvalde," the funeral home said the day of the shooting.

Even strangers have traveled from hours away to help those suffering in Uvalde.

Omar Rodriguez, the owner of a car detailing business, made 250 hamburgers to raise funds for the victims' families.

At a friend's lot on Main Street, Rodriguez set up a large grill, tables and supplies to cook while his family and friends grabbed rags and soap to wash cars for a donation.

The 24-year-old said he couldn't just stay at home, knowing he could do something to help.

"This is a good little town," Rodriguez said. "There's nothing but love here."

Patrick Johnson, 58, drove for seven hours from his hometown of Harleton, Texas, to Uvalde and set up a table filled with toys for children who haven't smiled in days.

"There's a lot of ways to be a blessing to people," he said. "Whenever something like this happens, I do my research and contact local law enforcement and ask 'what I can do?' What does your community need right now?"

Johnson, a father of four, said he broke down and wept when he heard about the shooting.

"I'm not even from this community, but I'm hurting. It makes you think about your own kids," Johnson said. "It makes you realize it could've been you, mourning your children."

- by Holly Yan and Aya Elamroussi, CNN