SAN JOSE, Calif. (KGO) -- Investigators say someone ignited a fire by throwing a flammable device through a window.
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It happened at the Timberwood Apartments on Seven Trees Boulevard just east of Monterey Road in San Jose.
Seven Trees Boulevard is still blocked off, firefighters remain on the scene cleaning up and making sure nothing flares up.
The flames were out at the scene around 8:15 a.m., but the ladders remained.
They were used by firefighters to rescue Ricky Ojeda and his brother from their balcony.
"They were firefighters. They were doing their job, doing what they've got to do," said Ojeda. "They were banging on my door trying to get me to get out. Get out. A. I was like, 'Woah.' It was a sight to see."
"Rescue is our number one priority," said Captain Mitch Matlow of San Jose fire. "And everything is focused on that until the rescue is complete. And this was a successful rescue."
Cellphone video caught the massive flames around 7:30 a.m.
One firefighter was injured and was sent to the hospital. He's expected to be okay.
Two apartments were destroyed. Five kids and five adults must find another place to live.
One of the residents was very emotional when he came home to see the destruction. A boy saw a man throw a, "fireball" into the apartment.
When asked if the crime would be investigated as an arson Matlow said, "Yeah. It is my understanding that fire investigators will be coming to take a look at the cause of the fire."
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Arson investigators say they will be on the scene through the rest of Thursday.