An early investigation revealed that the truck had a spare wheel in place of its left front tire, according to National Transportation Safety Board Vice Chairman Bruce Landsberg. That spare tire seemed to have failed, causing the truck to swerve in front of the van.

“A 13-year-old child was behind the wheel of the pickup truck,” Landsberg said during a news conference.

The wheel did not appear to be an emergency-use “doughnut” spare, but was similar to the rest of the tires. The left front tire had a steel rim that remained intact while the three other tires were extensively damaged.

The van was carrying members of the University of the Southwest men’s and women’s golf teams, who were traveling for a tournament.

Six of the student-athletes were killed in the crash, along with a coach. The 13-year-old pickup truck driver and his father, 38-year-old Henrich Siemens, were also killed in the crash.

The Texas Department of Public Safety identified the fatally injured coach and team members Wednesday as Tyler James, 26; Mauricio Sanchez, 19; Travis Garcia, 19; Jackson Zinn, 22; Karisa Raines, 21; Laci Stone, 18; and Tiago Sousa, 18.

Dayton Price, 19, and Hayden Underhill, 20, the two other people in the van, were listed in critical condition. Landsberg did not have an update on their condition on Thursday.

The Texas Department of Public Safety made the determination that the child was driving based on the identification of the remains in the driver seat following a post-crash fire, Landsberg said.

Landsberg noted that the NTSB is an independent agency that will investigate the crash but is not involved with potential criminal charges.

NTSB investigators are still looking into whether the vehicle recorders survived the crash to download data on how fast they were going prior to the accident. The speed limit on the highway is 75 mph.

“It was very clearly a high-speed, head-on collision between two heavy vehicles,” Landsberg said. “We have literally thousands of pictures that were taken by the various first responders, and there is no question about the force of impact.”

The NTSB preliminary report will be released in approximately two to three weeks, but a final report will not be released for 12 to 18 months, according to Landsberg.