WESTMINSTER, Texas – At least four people were killed, including an Anna High School student, and nine were injured in a horrific crash Tuesday afternoon on State Highway 121 in Collin County.

Authorities confirmed five vehicles were involved in the crash at State Highway 121 near County Road 528, just outside of Anna. Troopers were called to the scene shortly after 4 p.m.

According to Texas Highway Patrol, four people were pronounced dead at the scene. Nine people were sent to the hospital with varying injuries. All of those injured were sent either to Medical City McKinney or Medical City Plano.

Identities have not been released at this time, but the Anna Independent School District announced on Facebook that one of those killed was an Anna High School student, and another was a former Anna ISD student. The district says two other AHS students were injured.

"The Anna ISD family extends our deepest sympathies to the family and friends of these students. We are praying for all the victims and their families in this accident and for a full recovery for the others involved," the district said.

Officials closed down the road as they continued to investigate the crash scene. It reopened at about 3 a.m. Wednesday.

An initial investigation indicates a Pontiac Grand Prix was driving northbound on Highway 121 when it slowed down for an "undetermined reason," officials say, and set off a series of spin-outs and head-on collisions.

The Pontiac was first rear-ended by a Dodge pickup, causing the Pontiac to spin into oncoming traffic and hit a Ford Focus traveling in the other direction.

The Ford Focus then spun into oncoming traffic and was struck by a Ford F-450 utility truck.

A Subaru heading southbound was also struck by the Pontiac and rolled into a ditch.

Four people were inside the Pontiac, officials say. Two of them died at the scene and two others were sent to the hospital with serious injuries.

The three people in the Dodge pickup were taken to the hospital with non-life-threatening injuries.

Two people in the Ford Focus died at the scene, and two others in the vehicle were rushed to the hospital with serious injuries.

The driver of the Ford utility truck sustained serious injuries and was taken by air ambulance to the hospital. The driver of the Subaru was seriously injured and also sent to the hospital.