The blaze early Monday prompted fire officials to have personnel visit homes throughout the area, checking for smoke detectors and installing them where needed.
Killed were a 35-year-old Thomas Tong Vang, his wife, Pathao Vang, 23, and their two boys, Kelvin, 6, and Billy, 5, police said Tuesday.
``Everybody is having a really difficult time right now,'' said Rick Vang, a cousin of the father.
Family members and friends gathered at a home across the street to mourn the deaths. Neighbors said two of the man's brothers live on the same block.
Flames were shooting out the windows when crews arrived around 5:30 a.m. Monday, Battalion Chief David Shanahan said. They spent several hours fighting the blaze in frigid temperatures of around 12 degrees. Firefighters called in extra crews because of the strength of the fire and the weather.
Frozen hoses were curled next to fire trucks and ice coated the street where the burned shell of the house stood, icicles hanging from the roof.
Inside, firefighters assisted by a state fire marshal set up spotlights to investigate what caused the fire.
The fire department had not released a cause for the fire early Tuesday, but police said they had determined it was not a criminal act. Shanahan said the family had numerous space heaters in the home, and friends had reported the house had electrical problems.
The fire department sent firefighters to other homes in the surrounding neighborhood Monday to install smoke detectors if needed and check the batteries in others to prevent another tragedy.
Officials reminded residents to turn off space heaters when leaving a room and keep them away from anything flammable.
Rick Vang said many of the neighbors were related - part of a Hmong neighborhood where everyone knows and helps each other.
The victims were found somewhere in the center of the first floor, where they lived, said Fire Lt. Lawrence Jenkins. The occupants of the second floor were out of town at the time.
Investigators said three of the victims apparently were sleeping but the father may have awakened.
Two cousins of the father said he was hearing impaired and stayed home to watch the children while his wife worked.
``They think that he probably was awake enough to try and alert the others, but he was found in the hallway,'' Shanahan said.
Firefighters were alerted to the blaze by a neighbor who saw the smoke and flames as he left for work, Shanahan said. The neighbor got no answer when he knocked on the front door.
Most of the Vang family had moved from California over the last decade. Throughout the morning, cars carrying relatives pulled up at the end of the block to visit with the family.
Chong Vang said she was shocked when she heard the news about the family.
``I don't know what happened. You should wake up and get out,'' she said, shaking her head as she stared at the charred remains of the home.
As other relatives shivered on the street talking to reporters, two members of a community group came up to offer help and a hug.
``You belong to a strong community and we're here to help,'' said Toni Anderson, executive director of Lisbon Avenue Neighborhood Development. She said the group was ready to help the family any way they could, including possibly starting a collection for the upstairs tenants who lost all their belongings.
Lisa Vang, 12, said her family moved from California about five years ago. She said she played with the two boys, who were her cousins.
