Police said the incident happened at home in the 1400 block of Queen Street just before 9 p.m.
A 15-year-old girl was told by someone she knew to go to the house and she was robbed at gunpoint by a 19-year-old girl when she entered the home, according to police.
Police said an 11-year-old boy also threatened the victim with a machete. He was also arrested but not charged due to his age.
A 21-year-old man was charged while the 19-year-old escaped. Police are still searching for her.
Anyone with information is asked to contact police at 306-777-6500 or Crime Stoppers at 1-800-222-8477.