The young girl who allegedly received messages from the Texas gunman moments before his rampage told ABC News she has been asking herself "what if I could change the outcome" since seeing the news that her friend killed 19 students and two teachers on Tuesday.

"Ever since May 24th I have been guilt tripping myself, what if I could change the outcome, what if I could change his mind to not do this. I was too dumb to realize why he bought two Rifles on his birthday May 16th and ordered a package full with ammunitions not knowing what he was going to do with it," the 15-year-old girl, who asked to be referred to as "Cece," told ABC News.

The messages are part of an ongoing investigation into the shooter, law enforcement sources told ABC News.

Cece, who lives in Germany, said she met the accused gunman on the social media app Yubo where they would "join each others live" streams. The pair met on the app on May 9 before exchanging cellphone numbers, Cece said.

The messages reviewed by ABC News and other outlets appear to show that Cece did not respond to the gunman's threats until after news of the shooting broke and nearly all the texts are solely from the suspect. It is unclear if the messages were at all edited.

-ABC News' Will Steakin

The Donna, Texas, Independent School District has canceled classes after it received a "credible threat of violence," school officials said in a letter posted on Facebook. Donna is about 4 1/2 hours from Uvalde.

The threat is currently under investigation and classes will resume on Tuesday, the district said.

"In light of the recent events and in an abundance of caution we will be canceling school district-wide and staff will be working from home," the letter said. "The safety and security of our students & staff is our first priority."

-ABC News' Luke Barr

Nine of the deceased victims' bodies were released to funeral homes in Uvalde on Wednesday evening, Uvalde County Justice of Peace Eulalio Diaz told CNN.

More -- possibly all -- of the remaining bodies are expected to be released at some point on Thursday, according to Diaz. It will mark the beginning of the funeral arrangement process for many grieving families in the wake of the second-deadliest school shooting in U.S. history. There are two funeral homes in Uvalde, and both are offering free services to families of the victims.

"My job is to try and get them back home as quickly as possible," Diaz told CNN in an interview early Thursday.

In a county of less than 50,000 people, there is no medical examiner and the justice of the peace in the state of Texas assumes the responsibility of the county coroner, according to Diaz.

Diaz described his job of going in and assessing the bodies of the dead at Robb Elementary School on Tuesday in the immediate aftermath of the mass shooting. He said Irma Garcia, one of the teachers who were killed, was a former high school classmate of his.

-ABC News Ahmad Hemingway

There were four Border Patrol agents, members of elite specialized units, who engaged and stopped the elementary school shooter, along with state and local officers, a Customs and Border Protection official told ABC News.

One agent, who was part of the Border Patrol Tactical Unit, or BORTAC, held a shield as the group pushed toward the gunman's incoming fire, the official said.

Two BORTAC agents discharged their weapons along with one member of the Border Patrol's Search, Trauma and Rescue unit -- all part of the group of four.

At least one BORTAC agent shot the gunman, although it's unclear who among them killed him, the official said.

-ABC News' Jack Date and Quinn Owen