A community is grieving after a tragic house fire at a daycare in Pennsylvania claimed the lives of five young children earlier this week. According to reports, three of those who died were the children of a volunteer firefighter who had responded to a different call in the city when the house fire call came in.

It was approximately 1 am on Sunday when firefighters arrived at the Harris Family Day Care, a licensed daycare where children often spent the night, TODAY reports. Lawrence Park Township Volunteer Fire Chief Joe Crotty told NBC that volunteer firefighter Luther Jones' three children, two daughters, and a son, had died in the blaze. "Unthinkable," Crotty said. "It's really beyond comprehension." Jones had answered a call in a different area of the city before the daycare call came in.

Shevona Overton is the mother of four of the children lost in the blaze, La’Myhia Jones, 8, Luther Jones Jr., 6, Ava Jones, 4, and Jaydan Augustyniak, 9 months. “I’m just so hurt my babies are gone,” Overton told Erie News Now. “I love them dearly. I just hurt inside knowing that my kids were fighting and hurting in that fire. Every minute, I feel the same pain.”

When firefighters responded to the home, two teenagers who had escaped from a second-story window were yelling that there were babies in the home. The firefighters managed to pull seven people from the home, but only two survived. The owner of the home was also injured in the blaze.

The children who were killed in the fire ranged in age from 8 months to 8 years and Erie police and fire personnel are working to try to determine what caused the tragic house fire.

Valerie Lockett-Slupski is the grandmother of four of the children who died and said they were at the daycare because their parents were working overnight. “So we are all at a loss, trying to figure out how this happened,” she told GoErie.

The cause of the fire is still under investigation, but Erie Chief Fire Inspector John Widomski told GoErie that the fire was believed to have started in the front living room area on the first floor of the house. They still are unclear what set the fire off.

TODAY reports that investigators are looking at an electrical overload as a possible cause of the fire, and noted there was only one smoke detector in the home that was located in the attic.

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