Investigators believe a 4-year-old girl is one of four people killed in a multi-vehicle crash on Highway 400 on the weekend.

During a Periscope session on Monday morning, OPP Sgt. Kerry Schmidt said a young girl is believed to have died in the Friday night crash.

“The investigation still has a long way to go. I can tell you right now that we believe one of the deceased is a 4-year-old girl. There were three (victims) in that vehicle. Another victim in another smaller car. The three victims from that one car were believed to all be family and one of them was a 4-year-old girl.”

The 12 vehicle crash, which included three transport trucks, happened at around 9:45 p.m. in the southbound lanes of Highway 400 near Sheppard Avenue.

“I’ve never seen a collision of this magnitude and the fact that a fire consumed three of the vehicles – a trailer and two more cars – sadly, we’re having a difficult time identifying the deceased because of the fire,” he said.

The intense fire also caused significant damage to the highway. Crews spent part of the weekend repaving the road.

Autopsies are scheduled to be done on Monday, but Schmidt said three of the victims are believed to be female. He wouldn’t confirm the gender of the fourth victim.

The investigation is ongoing, and police are trying to determine if charges should be laid.

“The collision (investigation) is focusing on the actions of one of the commercial vehicles, to see whether the driver did not stop or slow down in time as traffic was slowing down.”

Anyone with information is asked to contact police or make an anonymous call to Crime Stoppers.

With files from CTV Toronto.