DIXON, Ill. -- Six people were found dead in a house early Tuesday in rural northern Illinois, the Ogle County Sheriff's Office said in a news release .

Police received a 911 call from the home just after midnight Tuesday from a home outside Dixon in the unincorporated community of Lost Nation, the sheriff's department said.

CBS News affiliate WIFR-TV reports the call came in as a report of smoke in the basement.

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Firefighters arrived to find "a fully engulfed residential structure fire," the sheriff's office said.

All six occupants of the residence died in the fire. The names and ages of the victims haven't been released. Ogle County Corner Louis Finch said the bodies were so badly burned that his office will need dental records to determine identification.

First responders from eight fire departments responded to the blaze. The sheriff's office said no other information was immediately available Tuesday morning.

The sheriff's office, Illinois State Fire Marshal and Illinois State Police are investigating the cause of the fire.

The home is located about 90 miles west of downtown Chicago.