Const. Ian MacDonald says that despite her serious injuries, the woman managed to phone 911 and report that a man had fled with her 18-month-old son.
MacDonald says the suspect was arrested in a nearby backyard and is the baby's father.
He says the 24-year-old man is well known to police and faces various charges.
The woman remains in hospital.
MacDonald says the child appears to be OK, but he didn't know if the boy was with family or in the care of the Children's Ministry.
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