Relatives of those feared to have been inside the home thanked their well-wishers earlier Thursday, but asked people to respect their privacy, noting that "our loss demands time and quiet reflection."
The relatives' statement, attributed to "the Boone and Pyle families," referenced four children -- Alexis (Lexi) Boone, 8, Kaitlyn (Katie) Boone, 7, Charlotte Boone, 8, and Wesley (Wes) Boone, 6 -- and their grandparents, Sandy Pyle and tech executive Don Pyle, who records list as the mansion's owners.
The six family members were believed to have been inside the mansion Monday morning when the fire broke out, according to relatives and neighbors.
"We wish to express our gratitude and appreciation for the love and support being shared with us during this tragic event," the families said in the statement. "We are blessed that so many family, friends, and neighbors have come together for us in our time of need."
It added, "Our love for our family is boundless. Our loss demands time and quiet reflection to process these feelings. We ask that you respect our need for privacy.
”Life is fragile," the statement concluded. "Make time today to embrace your loved ones.”
The statement also recognized "the dedicated efforts" of local and national responders.
Officials are still investigating the cause of the fire at the 16,000-square-foot mansion.
Crews started going through the wreckage Wednesday, according to ABC affiliate WJLA, a process that Bureau of Alcohol, Tobacco, Firearms and Explosives investigators said could take weeks.
The house was "built more like a commercial structure," Anne Arundel County Fire Capt. Russ Davies told reporters, so searching is a "time-consuming process."
For now, the fire is being handled as a criminal investigation, officials added.