A four-year-old girl and two of her family members are believed to be among the four people killed in a crash on Highway 400 last week.

On Monday morning, OPP Sgt. Kerry Schmidt provided an update on the deadly accident, which occurred in the southbound lanes of the highway near Sheppard Avenue shortly before 10 p.m. Friday.

According to Schmidt, 11 vehicles were involved in the crash, including three transport trucks.

“I’ve never seen a collision of this magnitude and the fact that that a fire consumed three of the vehicles, a trailer and two more cars, sadly, we are having a very difficult time even identifying the deceased,” Schmidt said Monday.

Three people killed in the crash, including the child, were travelling in the same vehicle. All occupants of that vehicle are believed to be female and members of the same family.

The gender of the fourth person killed in the crash is not known at this time.

Autopsies are being conducted on the victims today.

“We’ve been working very closely with the office of the chief coroner and forensic pathology, working on identifying the deceased, working to notify the family,” Schmidt said.

“We do believe we have spoken to all the family that are affected by this tragedy here.”

Schmidt called the accident “absolutely preventable.”

“This (crash) here has obviously touched a bit of a nerve with the circumstances around it, with the multiple fatalities,” he added.

The cause of the crash is still under investigation but Schmidt said the speed of one of the transport trucks may be a factor.

“I can tell you right now that the collision is focusing on the actions of some of the commercial vehicles, or one of the commercial vehicles, to see whether the driver didn’t stop or slow down in time as traffic was slowing down,” Schmidt said.

Any witnesses to the crash are asked to contact the OPP.

“You may not think it (the information) is very valuable but it could be the piece we are looking for,” Schmidt said.

No charges have been laid in the crash.