One person inside the home was found dead, while another resident was arrested -- booked for manslaughter, child endangerment and manufacturing drugs.
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"It's a quiet neighborhood. People are nice. And in the middle of the street, you have this guy who is doing something illegally," said neighbor Karen Lei.
Lei spoke to ABC7 News from the second-floor window of her red-tagged home on 22nd Avenue, which is next door to the house that exploded Thursday morning.
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Police say a narcotics lab was being operated inside the home. The suspect, 53-year-old Darron Price, was arrested on Friday.
"That's the right thing to do, because he's very destructive -- causing property damages and disrupting people's lives," Lei said.
"The suspect we arrested, Darron Price, we believe that was his primary residence," said SFPD officer Robert Rueca.
"He never introduced his family," said neighbor Albert Ng.
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Neighbors say Price lived at the house with his family. Although the two young children were not home at the time of the explosion, neighbors say Price's disabled wife and caregiver were inside.
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Ng said that after the explosion, the frantic, injured caregiver asked him to call 911.
"She ran across the street and told me to help, somebody's inside," Ng said.
The body of a woman was later found inside the rubble. First responders were seen removing tanks and canisters from the house that were filled with unknown substances.
The massive explosion rocked the neighborhood, blowing doors off hinges and shattering windows.
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Jerry Kwan was still cleaning up shattered glass from his mom's house five doors down.
"I find it amazing it could happen in a residential area so quiet," Kwan said.
Neighbors say they never suspected anything unusual was happening inside the home.
"I know people say, you lived next door, but I'm telling you they never invited us to anything. You just don't know what's happening inside people's homes," Lei said.