MONTREAL -- As Quebec provincial police continue to investigate a deadly weekend crash on Highway 40, one witness said some of the vehicles involved were "100 per cent" street racing seconds before the carnage unfolded.

"These guys went by, they had to be going 165-170 (km/h). They were flying," they said in an interview Tuesday.

The witness said both cars cut him off on the highway on the West Island — a white car passing him on his right and a red car passing him on the left.

"When the white car cut me off I pulled up on the brakes. I wasn't going to be around these guys. And then I see the white car and two wheels hit the gravel and start spinning," he said. 

"It all happened so fast."

Seconds later, he caught up to the crash scene to see a red Audi mangled and upside down in the eastbound lane near Saint-Charles Boulevard in Kirkland. 

It’s believed a light-coloured Ford Focus was pulled over on the side of the highway when the red car crashed into it. 

Two of the vehicles involved caught on fire due to the impact. One 15-year-old girl was pronounced dead in hospital, while another man in his 20s is considered a suspect and is clinging to life in hospital with serious injuries. 

“This could have been me if I hadn’t pulled up,” said O’Donoghue. 

The Surete du Quebec have only said they suspect car racing as a possible cause of the crash since their investigation is still ongoing. They did say that the male suspect, who has not yet spoken with investigators due to his condition in hospital, could face a charge of dangerous driving causing death. 

Two other people suffered serious injuries, but their condition has stabilized.

Friends of Véronica Gashi, the girl who died in the crash, are mourning her death on social media. 

“You are gone too far my beautiful, rest in peace,” wrote Adriana Sclifos on Facebook. “We will miss you.”