At about 6:45 p.m., Wakaw RCMP responded to One Arrow First Nation after several disturbances were reported.
During one of these incidents, a woman allegedly entered a home uninvited, assaulted a woman, then left with her four-month-old son, police say.
The child was later found by his mother unharmed at a second residence on One Arrow First Nation.
Police say he was separated from his mother for about 30 to 45 minutes.
According to police, the suspect is known to the victim.
A warrant for the arrest of Tori Sutherland, 26, has been issued.
Anyone who sees her is asked to call 911 immediately. Do not approach her, say police.
She is described by RCMP as having brown eyes, black hair and a thin build. She is about five-feet-four inches and weighs 115 to 120 pounds.