The first 911 call came just past noon on Wednesday, nearly 20 minutes before a fatal crash killed more than a dozen seniors.
A white pickup truck was driving erratically on a highway, a caller told a county dispatcher in South Texas.
Five minutes later, at 12:07 p.m., the same caller called authorities in a neighboring county.
"I'm following this guy. He's in a white Dodge dually. He's all over the road, both sides," he said. "He's going to hit somebody head on, or he's going to kill his own damn self."
By 12:20 p.m. the white truck had veered into the opposite lane and plowed into a church bus carrying seniors who were returning home from a retreat. The accident happened on a highway in rural Uvalde County, more than 90 miles west of San Antonio. Thirteen people, including the bus driver, were killed.
Authorities have identified the driver of the pickup truck as 20-year-old Jack Dillon Young, according to media reports.
The caller, Jody Kuchler, told reporters that Young was texting when he collided head on with the southbound bus. The Uvalde Police Department and the Texas Department of Public Safety did not return calls and email from The Washington Post. Investigators have not confirmed whether texting played a role in the crash, but a spokesman for the state agency told NBC affiliate KXAN that Young appeared to be distracted when he drifted into the southbound lane.
The National Transportation Safety Board is also investigating. The federal agency has declined to comment on what caused the crash.
The Post was unable to reach Kuchler on Saturday, but he told KXAN that he followed the pickup truck for about 20 minutes after he noticed the driver was driving recklessly. Kuchler and his girlfriend took a video as they tailed the truck. The footage shows the vehicle drifting in between lanes for several miles. Kuchler can be heard in the background, talking to 911 dispatchers.
"Somebody needs to take this guy off the road . . . He's going like 80 miles an hour right now," said Kuchler, who was one of the first people at the scene of the crash.
Kuchler told the San Antonio Express-News that he briefly talked to Young, who was unable to get out of his truck after the crash.
"He asked me if I could help him. I told him, 'Son, do you know what you just did?' Kuchler told the paper. "He said, 'I'm sorry, I'm sorry. I was texting.'"
Kuchler also said he tried to help the bus passengers and found a few already dead, while others were still moving.
"The elderly people that was in that bus, them women that was still alive, none of them was crying. None of them complained. None of them asked for help," he told KXAN. "They just looked at me whenever I told them to hang on, help's on the way."
All of the victims were members of the choir at the First Baptist Church of New Braunfels, a town about 35 miles northeast of San Antonio. They had just attended a three-day retreat, The Post's Samantha Schmidt reported. They were on their way back to the church when the crash occurred.
Among those who were killed was retired teacher Murray Barrett, the bus's driver and a retired school teacher, the San Antonio Express-News reported.
The only person in the bus who survived was in serious but stable condition, the church said in a statement Wednesday.
The police department has lowered the flags outside the station to half staff to honor the victims.
"The Uvalde Police Department would like to extend our deepest condolences to all of the families who are mourning their loved ones. May God give you strength during this difficult time," the police department wrote on its Facebook page.
No criminal charges have been filed.
Officials said Friday that investigators with the National Transportation Safety Board hope to talk to Young, who is hospitalized in stable condition.(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)