Three cousins as young as six suffocated in 35C heat after accidentally locking themselves in a car.
Agatha Morales, nine, Shamel Alghela Morales, eight, and Pauline Keziah Morales, six, were found dead in the green car after trying desperately to escape for hours.
It is understood the cousins had opened a door of the car parked on Agatha's driveway and climbed inside to play.
The kids locked it behind them and were unable to get out again on Monday in Bataan province, Philippines.
A friend of the young girls noticed four hours later they were lifeless.
She alerted Agatha's dad Jessie Morales, 31, in the house but, despite his best efforts, the oil refinery worker was unable to save the kids.
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"They were not able to breath because of the heat inside," the heartbroken father said.
Police are investigating whether or not Jessie and his partner are responsible of negligence.
"The father opened the door but the kids were not responding. He brought them to the hospital where they were pronounced dead due to suffocation," said Dennis Orbista, Bataan Police chief.
"To parents of children who are of the same age of the victims, always watch over the children because out of curiosity, they play with all things in the surroundings."
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But the devastated family of the victims said that they believe it was an accident and no further investigations should be conducted.
They have instead blamed a faulty lock on the car door which allowed the children to climb inside to play but prevented them from opening the door to escape.
The mercury has exceeded 30C in Bataan for each of the past 10 days.
