"I want to report a missing person," Celis calmly explained to the dispatcher. "My little girl, who is 6 years old -- I believe she was abducted from our house."
In a second tape from later that same day, Celis' 14-year-old son speaks to a dispatcher briefly before handing the phone to his frantic mother, who is asked to provide details about Isabel's appearance and what she was wearing when she was last seen the night before.
ABC News reported Sergio Celis has been barred from contact with his two sons. However, police have declined to explain the decision, saying only that it does not mean Celis has been implicated as a suspect in his daughter's disappearance.
"A voluntary agreement was reached between Child Protective Services and the parents to restrict access or, voluntarily, for Sergio to give some space and distance away from the two older children," said Tucson Police Chief Roberto Villasenor.
Isabel Celis was reported missing at 8 a.m. April 21, when her father went to wake her up. She was missing from her bed, and the window was opened with the screen removed. After her father reported her missing, police interviewed 15 registered sex offenders in the area, searched homes and even a nearby landfill. Police say they have received more than 1,000 tips.
Notable deaths of 2014 [PHOTOS]