WATCH: Firefighter's helmet cam captures dramatic rescue

The Fresno Bee reports that three children, ages 1, 3 and 4 years old, were alone in the apartment when the fire broke out Sunday in Fresno, California.

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One neighbor who spoke to the Bee's reporter said bystanders had no idea that there were children home alone.  The mother, officials told the newspaper, returned after the fire started and told neighbors where the children would be found.  They then started breaking windows trying to get them out.

When rescue crews arrived, one firefighter entered the burning building, with little to no visibility, and found first the baby, then a second child, and eventually a third child, racing to get them into fresh air.

In the video, it is difficult to see through the smoke, but at one point you can see flames and hear the sound of glass breaking.  When the firefighters got the children outside, they were unconscious, covered in soot, due to the smoke KABC reported,

The three children are in critical condition with a few burns and smoke inhalation, KMPH reported.

Child Protective Services has custody of the three children, according to KMPH, while an investigation as to why and how long the children were alone continues.