ANNAPOLIS, Md. (AP) — As fire officials search for six people missing since a massive fire destroyed a waterfront mansion in Maryland's capital city, they are focusing on the charred ruins where relatives say they believe the missing people were at the time of the fire.

Investigators will likely begin searching what remains of the 16,000-square-foot multi-million dollar mansion on Wednesday, said Russ Davies, a spokesman for the Anne Arundel County Fire Department.

Davies has declined to identify the family members. On Tuesday, he said only that relatives believe the six — a man and woman and their four grandchildren — were inside the mansion when it caught fire.

"We know who's unaccounted for," said Davies said. "If you look at the damage, you know, it would not be a stretch to think that if there were occupants that they did not survive the fire."

Davies said once inside, crews will begin stabilizing the wreckage and pump out tens of thousands of gallons of water from the basement.

"We're going to be talking about days not hours to get this done," Davies said.

The blaze reduced the mansion to a scorched stone framework Monday. Fire officials said nearly all of the structure collapsed into the basement. The mansion had no sprinkler system, officials said.

The flames took hours to put out after the fire began before dawn Monday on the outskirts of Annapolis.

The fire was reported about 3:30 a.m. Monday by an alarm monitoring company and a neighbor who spotted flames at the mansion. Officials said Tuesday that it is unclear whether the alarm went off inside the home, alerting the residents to the fire.

Online records of the Maryland Department of Assessments and Taxation list the dwelling as the primary residence of homeowners Don and Sandra Pyle.

Some 85 firefighters were called in from several jurisdictions to fight the fire. Davies said because there was no fire hydrant in the area, firefighters shuttled water tankers to the site and stationed a fire boat at a pier near the property to bring in water.

Davies said hot spots took about 10 hours to extinguish before operations were scaled back around nightfall. One part of the scene was still flaring up Tuesday, and Davies said crews were monitoring it and extinguishing it as needed.

Agents with ATF were on the premises Monday afternoon.

Special Agent David Cheplak, a spokesman for the ATF's Baltimore field office, said there was no evidence at this point of foul play. Still, Captain Robert Howarth, commander of the fire and explosives investigation unit, said Tuesday that the site is currently being treated as a crime scene. Howarth said that is common practice when there are no eyewitnesses, and means only that whatever is recovered in the investigation will be admissible in court.

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