On Friday, members of the North Central Texas College softball team were traveling back from a scrimmage with a nearby university when a tractor-trailer crossed over a highway median and crashed into the team's van, authorities told the Associated Press.
Three of the women died at the scene, and a fourth died at the hospital, according to Oklahoma Highway Patrol Capt. Ronnie Hampton. Fifteen others are reportedly injured. It's unclear exactly how many people were aboard the bus, and the names of the victims have not yet been released. The driver of the school van did not seek medical treatment.
"What we do know is that the semi was headed north on I-35 when he departed the roadway and entered the southbound lanes," Hampton told The Oklahoman about the tractor-trailer.
"When it impacted the bus, it just kept going and went off the side of road. ... We knew we had a two-vehicle accident by what we saw at the scene. ... But it took about an hour before we found the semi."
The crash occurred south of Turner Falls on I-35 in Oklahoma. Hampton said that the incident is being investigated "like a homicide."
"Both drivers ... We will run toxicologies on them, which is standard with something like this," he said.
The captain added, "We don't know if [drugs or alcohol is] the case here ... but something happened to cause him to depart the roadway and impact the other vehicle."
On Sunday afternoon, the National Transportation Safety Board Tweeted that its investigators found "no evidence of braking or evasive maneuvers by" the truck before it hit the bus.
NTSB investigators estimate truck traveled 820 feet through median at a shallow angle before striking bus. #oklabus
NTSB investigators have found no anomalies with brakes on the truck involved in the Oklahoma truck/bus crash. #oklabus