A California mom is calling Police Officer Matt Olin and "angel from God" for rushing to her 4-year-old daughter's aid after she nearly drowned in the family pool and had stopped breathing.

The girl's mother, Sara Villasenor, says her daughter Nina and 6-year-old son Rikki were swimming in her dad's pool in Costa Mesa, Calif., Monday evening while their grandpa was watching from inside. Villasenor said she went inside to use the restroom and two minutes later, heard her son screaming.

Nina had slipped off her floaties and went underwater.

"All I see is my daughter completely blue, not breathing, lifeless, foaming at the mouth," Sara told ABC News today.

Rikki was able to push his sister Nina towards the steps, where Nina's grandpa picked her up and began performing CPR.

The mom took her daughter inside and called 9-1-1.

"It was a hysterical call," Sgt. Matt Grimmond told ABC News. "She was screaming hysterically saying 'My child fell in the pool, she's not breathing.'"

Officer Olin responded first and found the girl turning gray, so he started performing CPR.

"He is an angel from God," Sara said. "He was at the right place at the right time."

After about a minute, Nina started breathing again.

Officer Matt Olin with 4 year-old Nina and her brothers three days after the near-drowning. Courtesy Sara Villasenor

"I just knew that God was there and she wasn't going to go anywhere," Villasenor said. "When he got that first breath going, it was such a huge sigh of relief."

Nina was taken to the hospital and stayed overnight. She finally started talking and responding about eight hours after the incident. Her mother said Olin even showed up at the hospital to check on Nina. She said she can't thank him enough for his care, concern, and humility. "I owe my life to him and am forever indebted to him."

4-Year-old Nina recovered in the hospital after nearly drowning in a pool. Courtesy Sara Villasenor

Sgt. Grimmond says the incident serves as a reminder for parents to never leave children unattended in the pool, jacuzzi or bathtub.

"In less than a minute these kids can die," Grimmond said. "That's what saved her, us getting there quick. Every second oxygen is leaving the brain, it's another second that kid is not getting back."

"If we saved at least another life through Nina's story, that's my daughter's purpose," Villasenor said. "Don't take your eyes off your babies. Keep them within arm's reach at all times."