Mounties have arrested a woman allegedly involved in a Surrey hit-and-run that left a five-year-old boy critically injured.

Staff-Sgt. Murray Hedderson said the woman, believed to be in her 20s, was in contact with RCMP before turning herself in to a district office on 148 Street Saturday afternoon.

The name of the driver has not been released and no charges have been laid, he said.

He sustained severe head injuries and was airlifted to BC Children’s Hospital in Vancouver for treatment. Ambulance personnel confirm the boy suffered life-threatening injuries.

The driver fled the scene in a suspect vehicle described as a newer-model, four-door grey Mercedes with tinted windows and large stock rims.

Surrey RCMP then located a similar vehicle in the driveway of a home a few blocks away after tips streamed in from the public.

In Pictures: Surrey RCMP search car after hit-and-run critically injures 5-year-old

It was seized “and will undergo extensive mechanical and forensic inspection,” they said in a news release.

Police said the suspect was not the owner of the vehicle and it is unclear if she even lived at the home it was found at.

A little girl who lives near the victim and witnessed the accident told CTV News the boy had been walking with his older brother and grandpa.

“He didn’t wait for his brother or grandpa to cross the road,” she said. “As he was walking or running a car just comes out of nowhere and hits him, and he goes twirling onto the side of the road and he’s just lying there and I don’t hear any response from him.”

The five-year-old victim remains in intensive care.

With a report from CTV British Columbia’s Scott Hurst and Michele Brunoro