East Vancouver parents were terrified May 9 when the mother was assaulted inside her vehicle while her four-month-old baby was in it.
"This obviously was very terrifying for the people involved," Vancouver Police Department spokesperson Const. Tania Visintin said.
The woman received minor injuries.
The 32-year-old victim was in a vehicle parked near Commercial Drive and East 2nd Avenue, Visintin said.
Bystanders and witnesses intervened and held the person until police arrived and took her into custody, VPD said.
A 26-year-old woman who remains in police custody is facing an assault charge.
The VPD says the victim did not know the suspect.
The case, which could involve some mental health issues, remains under investigation.
"We don't know the motive," VIsintin said. "We don't know what the suspect was doing prior to the interaction with this woman."
Anyone with information about the alleged stranger assault is asked to call VPD’s Special Investigation Section at 604-717-0601.
With files from Lindsay William-Ross