What started as a minor fender bender in Fort Worth on Monday evening escalated into a major crash, leaving three persons dead and three others injured.

Fort Worth Police responded to reports of a crash on northbound Interstate 35W near Berry Street at about 9:09 p.m. on September 11. Officer Daniel Segura, a department spokesperson, said that two vehicles were involved in a minor collision on the highway, and the drivers pulled over to the left-hand shoulder of the road to exchange information.

Another truck pulled over to aid the two drivers, partially blocking the roadway.

Shortly after that, an 18-wheeler collided with all three vehicles. This was followed by another 18-wheeler that also crashed into the other vehicles.

“I’ve seen several accidents, but not one as big as this one in the past few months,” said Segura.

“So we have a total of five vehicles involved. So far, we have six victims. Three of these victims have been confirmed fatalities,” Officer Segura said in a video posted by the department.

The three surviving victims were transported to the hospital in critical condition.

Officials subsequently shut down both the northbound and southbound lanes of traffic between Berry Street and Seminary Drive due to the large amounts of debris scattered on both sides of the freeway. The lanes were reopened hours later, at around 2 a.m., WFAA reported.

The names of the victims and the survivors have not been released. The spokesperson could not provide the ages or genders of any of the victims.

Special traffic investigative units and support units are still investigating the cause of the multiple collisions. Officials have not yet determined what caused the initial minor crash, where each victim was during the event, or which vehicle each victim was in.

“It’s a huge scene on the freeway, so it’s going to take a while to determine where everyone was at the time of the accident,” said Segura.