A witness to a deadly Texas wreck involving a church minibus says the driver of a pickup truck that crossed the center line repeatedly apologized and acknowledged he had been texting while driving.

Jody Kuchler told The Associated Press on Friday that he was driving behind the truck and had seen it being driven erratically prior to the collision on a rural two-lane road about 75 west (120 km) of San Antonio.

Kuchler says he spoke with the driver as he was pinned in his truck Wednesday moments after the collision with the bus carrying senior adults with First Baptist Church of New Braunfels, Texas.

Kuchler says he told the driver, "Son, do you know what you just did?" He says the driver responded by repeatedly apologizing.

The Texas Department of Public Safety has identified the driver as 20-year-old Jack Dillon Young.

Thirteen people on the bus were killed and the lone survivor remained hospitalized Friday.