A pregnant mother and her two children were killed in a raging, two-story house fire in Philadelphia that officials say was intentionally set, with neighbors and family recalling how the “devastating” blaze broke out “really fast” early Friday and caused the kids’ grandmother to jump out a window with a “baby in her arms.”

“We looked out the window, it was engulfed in flames,” neighbor Yessenia Nieves told local NBC affiliate WCAU about the early morning fire in Philadelphia’s Strawberry Mansion neighborhood that claimed the lives of Ashley Thompson and her two children, Alayna and Asad, both 6. Local Fox affiliate WTXF reports that Thompson was seven months pregnant, citing interviews with family members.

At least one person has been taken into custody for further questioning, according to WTXF, but charges have not been filed.

“I couldn’t even imagine in my mind who would want to hurt three babies and a pregnant girl,” said Chyna, a relative and roommate who spoke to WTXF and other outlets Friday and declined to give her last name.

“This morning I’m getting a call that the whole house is on fire and my family is gone,” she said, according to local ABC affiliate WPVI.

“It don’t even seem real,” Chyna continued. “It’s a dream — she’s going to wake up tomorrow and call me.”

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The Philadelphia Fire Department says it’s working with the police department and the Bureau of Alcohol, Tobacco, Firearms and Explosives to determine what caused the deadly fire. Arson detection dogs and other tactics are reportedly being utilized.

“You all took my family,” Chyna said in reference to whoever is responsible, according to WTXF. “Including that baby she had in her stomach that was very healthy, and she was about to have. That’s a tragedy.”

Nieves told reporters that by the time she got out of her house with her husband, the children’s grandmother “had already jumped out the window with the baby in her arms,” per WTXF.

“There was no going back in to help anyone else,” Nieves said. “It’s just devastating. Really sad, the whole situation.”

Thompson was found dead on the second floor of the home, while her children were pronounced dead at the hospital after arriving in critical condition.

Police say the investigation is still ongoing.