The National Transportation Safety Board on Thursday released their preliminary report on the deadly church bus crash that killed 13 near New Braunfels on March 29.

The crash happened when a truck, driven by 20-year-old Jack Young, crossed into the opposite lane of traffic and crashed head-on with the church bus, killing all but one person on board. Young was hospitalized following the crash.

The NTSB report references a 14-minute video recorded by a witness which shows the driver of the truck crossing over the solid white line at the edge of his lane 37 times and entering the grass on the side of the road at least five times. The video also shows the driver cross the double yellow median line into the opposite lane of traffic 19 times, at one point crossing completely into the wrong side of the road. The video also indicates that the truck traveled at a fairly consistent speed -- between 67 and 71 miles per hour. The speed limit on the road is 70 miles per hour.

According to the report, Young told a witness that he had been texting while he was driving. He told the NTSB that he was checking his phone for a text message at the time of the crash. The NTSB will review his phone records over the coming weeks.

Young also told the NTSB that he had taken prescription medications before the crash. Several of those medications, as well as marijuana, were found in his truck. Toxicology results are still pending.

The investigation showed that everyone on the bus was wearing a seatbelt. No mechanical defects were found in either vehicle.

The NTSB investigation into the crash is ongoing.