Christine Mustafa was last seen by a coworker as she was leaving work Wednesday morning. Mustafa's sister was the last person to hear from her, later that day.
According to police, on Thursday, Mustafa did not arrive for her scheduled work shift, prompting family members to call police for a welfare check.
"She wouldn't just leave her 8-month old child and disappear or vanish like that," said Mustafa's sister, Linda Donaldson.
No one answered at the home near 20th Place and Robin Lane, but police said Mustafa's boyfriend arrived as they were at the residence and told officers she had left for work earlier that morning on foot.
"Christine is the sweetest person I know," her friend Kerri Martinez said. "She's nice to everybody and always happy."
Detectives on Tuesday served a search warrant at her home in an effort to find clues to her disappearance.
Mustafa's family says they are extremely concerned because it is out of character for her to leave without contacting them, and they are especially worried because Mustafa left her wallet and cell phone behind.
Detectives are asking anyone with information to contact Silent Witness at 480-WITNESS (480-948-6377).
On Saturday morning, a search party will be heading out at 5 a.m. in hopes of finding Mustafa.
The group will be meeting at the corner of Mariopsa Grande and 20th Street at the desert entrance. Volunteers as asked to park in the dirt area or on the side of the street. People are urged to bring binoculars and water.