A 22 year old man is in custody after police say he stole a vehicle and demanded a woman who is eight months pregnant get out of her car.

At around 8:30 p.m. Sunday, in the area of Alma Street and West 4th Avenue, police say the woman was sitting in her idling car, while waiting for her husband, when the suspect got in and told her to leave.

Police say the suspect threatened the woman with a weapon.

Witnesses tell CTV News Vancouver it was a knife. The suspect then fled in the vehicle. 

"Forty-five minutes later we received information about a collision," Const. Steve Addison said in a news conference.

A witness told CTV News on scene, that a dark SUV was seen crashing into multiple cars and objects in the area. That SUV eventually came to a stop after crashing into a tree on West 70th Avenue between Granville Street and SW Marine Drive around 9 p.m. 

The driver of that SUV allegedly took off on foot and fled the scene.

"This is a traumatic experience," Addison said.

While the woman was not severely injured, Addison explained that because of her late-stage pregnancy, "we ensured she received medical attention and was treated appropriately."

Vancouver police swarmed the area after the incident, and set up perimeters around it. A police K-9 unit was brought to assist in tracking down the driver. There were reports that heavily armed police officers had set up checkpoints mid-span on the Oak Street and Arthur Laing bridges.

Police arrested the suspect a short time later and he remains in custody.

"This individual has had a number of recent contacts with police for a variety of incidents," said Addison.

Forensics officers were seen taking photos and gathering evidence of the crash.

No charges have been laid, but police say they're recommending charges in relation to carjacking and the collision. 

Police also said there were no major injuries reported.