PHOENIX -- (KNXV) -- It's been 13 days since Christine Mustafa disappeared.
The young mom from north Phoenix supposedly left for work, leaving behind her car, her wallet, credit cards and--most importantly--her 8-month-old baby.
Since her disappearance, family members have spent days searching the area around her home.
Her live-in boyfriend, who is also the baby's father, says they had gotten into an argument and she just never came back home from work.
A search warrant ABC15 has obtained indicates he may know more than he is letting on.
Phoenix police are now calling the man a "person of interest" because he lived with her, but they stress he is not a suspect in the case.
The court documents state in the days leading up to May 10, Mustafa confided in her sisters that she was afraid of her boyfriend. She was planning to take her baby, leave and get an order of protection against him.
Court documents state her boyfriend was allegedly calling her repeatedly at work with accusations of cheating, and even threatened to kill her.
After she failed to show up at work and seemingly vanished without a trace, court records state police picked the locks and made entry into Mustafa's home and searched the house but did not find Mustafa.
Officers did find her purse which contained her wallet, social security card and credit cards in plain sight. Her cell phone was discovered on the bathroom floor between the tub and toilet.
As they were investigating, authorities said her boyfriend arrived home and told police she left after a verbal argument, but didn't take her Nissan Cube because it had a flat tire. Court records state police did not observe a flat tire on the vehicle.