The driver of a truck involved in a church minibus crash that left 13 people dead may have been texting just before the vehicles collided, a witness claims. 

Jody Kuchler described seeing a truck swerving into the opposite lane several times as he was driving with his girlfriend along US Highway 83 around 75 miles west of San Antonio, according to BuzzFeed News. 

Kuchler revealed he was so concerned about the vehicle that he reported it to the local sheriffs' department to get it taken off the road. 

In an audio of the 911 call obtained by KSAT news network, Kuchler pleaded with authorities to send someone out.  

"He's going to hit somebody head on or he's going to kill his own damn self. Somebody needs to get this guy off the road," the audio records.

Kuchler then said he spoke to the driver following the crash and that in their exchange, he admitted he had been texting at the wheel moments before.

"He said, 'I'm sorry, I'm sorry. I was texting,'" Kuchler said, according to BuzzFeed News. "I said, 'Son, do you know what you just did?'"

Terry Williams, of the National Board of Transportation Safety told BuzzFeed News that the investigation was still in its early stages and that it was taking driver distractions into consideration, although he refused to comment specifically on Kuchler's claim. 

The minibus was carrying older members of First Baptist New Braunfels Church home from a three-day retreat.  Only one passenger survived the accident and remains in a critical condition in a San Antonio hospital.  The driver of the truck also remains in hospital. 

Lead federal investigator Jennifer Morrison told reports that most of the passengers had been wearing their seatbelts at the time of the accident.  

The congregation of First Baptist New Braunfels has set up a relief fund in support of the victims' families.