Mother and Daughter, 12, Killed in Calif. Apartment Fire, Grandmother Suffered 'Significant Burns'

A mother and daughter are dead after flames broke out in their California apartment on Tuesday night.

The Downey Fire Department was called about an apartment fire on Tweedy Lane at 10:47 p.m. local time, the DFD said in a press release issued on Wednesday.

Responding firefighters were met with "heavy smoke and fire from a garage in a condo complex" and were told that possibly three people were trapped inside, the DFD said.

"Once on scene crews found one patient in front of the building suffering from significant burn injuries," the DFD said, adding that the individual is recovering at a trauma hospital.

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The two other occupants were found shortly after. One was pronounced dead at the apartment, while the second, a minor, was taken to Los Angeles County+USC Medical Center and declared dead shortly after.

It took over 35 local firefighters roughly 25 minutes to put out the blaze, per the DFD.

Authorities are investigating to see how the fire started.

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The minor victim is said to be a 12-year-old girl, and the other is reportedly her mother, according to multiple news outlets. The individual recovering in the hospital is the girl's grandmother. Their identities have not been made public.

"They encountered high heat and low visibility and extreme fire conditions," Fire Department Battalion Chief Jorge Villanueva said, KTLA reported.

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Firefighters found the mother and daughter in an upstairs bathroom in cardiac arrest, per the outlet.

Fox 11 reported that arson investigators were at the apartment. The fire is said to have started in the garage before making its way throughout the apartment. It didn't impact any other units.

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When reached by PEOPLE, the Downey Fire Department did not confirm the victims are a mother and daughter, nor the minor's age.