SIOUX FALLS, S.D. -

We bring you a story of two children in trouble and others who stepped in to help. Sioux Falls Police say a 9 and 12-year-old boy nearly drowned in an indoor pool at an apartment complex on the east side of town. Luckily, other children who witnessed the event knew what to do.    

A day at the pool turned into this scene at the Timberland Village Apartments on Friday night. Police say a 13-year-old girl invited friends over to the complex to swim. The girl went into the deep end, which was 9 feet, and her two younger brothers followed. When she got to the side of the pool, she noticed they were both underwater.

Officer Sam Clemens said, "One of the kids with them jumped in, was able to get the 9-year-old out. They started doing CPR on him. The other 12-year-old, she wasn't able to get him out of the bottom of the pool because he was too heavy."

Police say an employee working at the complex helped the kids pull the boy out of the pool. CPR was given until emergency crews arrived. Health experts say kids are good at knowing when something isn't right.

"They also see CPR on T.V., surprisingly kids adopt that information very, very easily," said Travis Spier, the Director of Simulation at Sanford Health.

"Kids are amazingly resilient and they're fast learner and so they never cease to maze me when they step up in a moment and take training they've had and apply that to the moment," said Eastern South Dakota American Red Cross Executive Director Jennifer Ross.

Children as young as elementary school age are taught what to do, but Ross says it's important to teach people often enough that it becomes muscle memory which often helps people override any panic.

Spier said, "The focus really now in CPR is optimal compression and so the quality of the compression is one of the key factors."

"Knees up against the patients arm and then we're going to do compressions at a rate of 100 to 120 beats per minute," said Spiers and he starts chest compressions on a dummy.

Spiers says it's also ideal if those chest compressions go down two inches when doing CPR on an adult.

While Spier says many worry they aren't qualified to give CPR, he says it could save a life and it's likely that it will be someone you know.

"It's better to do something than nothing at all," said Spier.

We're told the 9-year-old is in stable condition and the 12-year-old is in critical condition. While police say the children were unsupervised no charges have been filed.

If you would like to learn more about CPR or First Aid Classes, you can visit RedCross.org or Sanford American Heart Training Center at (605) 328-6327.