SAN LEANDRO (CBS SF) — An intense fire roared through a mobile home in San Leandro early Thursday, killing the couple who lived there, authorities said.

Alameda County Fire Department spokeswoman Aisha Knowles said that the blaze was reported 5:27 a.m. at 285 Santa Susana in the Mission Bay mobile home park.

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Arriving firefighters found the home fully engulfed in flames and could not enter the burning structure to save the residents.

“The structure was fully involved when we arrived,” said fire battalion chief Mark Carter. “There was fire coming out of every window, every door…It was not a situation where we could make an effective rescue due to the fire activity.”

The fire was extinguished within 15 minutes but the intense flames had completely gutted the building and melted the metal walls.

The identity of the man and woman killed were not released.

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David Salsedo was a friend of the couple who raced to the scene after seeing a report of the fire on television.

“I’m shook up,” he told KPIX 5. “They were very good people. She was very lovable. She always gave everybody a hug…I’ve known her for a long time.”

Neighbor Suzi Hasselkuss said she heard an explosion.

“I heard an explosion,” she said. “Then I heard people racing up the street. Someone was frantically honking their horn.”

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The cause of the fire remains under investigation.