Ikram Mohamud, 25, and her brother, 21-year-old Said Mohamud, found the girl just before noon at 8826 E. Florida Ave.
The Arapahoe County Sheriff's office says the victim was swimming with several children in the pool when she swam into the deep end and could not touch the bottom.
According to deputies, the girl was "flailing" around then began floating face down in the pool.
Another child ran to the nearest apartment, which belonged to the Mohamud's, to get help. The pair first called 911 and then ran to the pool where Said jumped in to rescue the victim, according to deputies.
Ikram reached emergency medical dispatcher Diva Miranda.
"Do you know how long she was in the water?" Miranda asked on the 911 call.
"I have no idea. This child just came screaming and I just get out of my bed and she was like, 'Help, help.' I have no idea what was going on," said Ikram.
Miranda then gave Ikram gave directions on how to open the girl's airway.
"I need you to place one of your hands on the child's forehead. I want you to put your other hand underneath her chin," said Miranda.
After tilting the victim's head back, Ikram noticed the girl was breathing but "gasping for air."
Click here to listen to the entire 911 call.
When sheriff's deputies arrived at the scene, the girl was lying on the ground near the pool, but conscious and breathing.
Paramedics took the girl, who was accompanied by her mother, to a local hospital.
Authorities say the Mohamuds' efforts saved the 12-year-old girl's life.
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