ABC News January 24, 2015

Annapolis, Maryland, Mansion Fire: Searchers Find Fifth Body

WATCH: Two More Bodies Found at Maryland Mansion Fire

Investigators found a fifth body in the rubble of a mansion in Annapolis, Maryland, that caught fire earlier this week.

The fifth body found at the home of Don and Sandra Pyle wasn't immediately identified by the Anne Arundel County Fire Department. The Pyle's 16,000-square-foot home caught fire Monday morning and quickly spread throughout the structure.

The couple had four of their grandchildren - Alexis (Lexi) Boone, 8; Kaitlyn (Katie) Boone, 7; Charlotte Boone, 8; and, Wesley (Wes) Boone, 6 - at their home at the time, according to relatives. All six are believed to have died in the four-alarm fire, though it's unclear what caused the blaze.

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Don and Sandy Pyle are seen in this undated family handout.
Family Had Fun Night Hours Before Fatal Blaze Maryland Mansion Mystery: Family Missing as Home Burns to Ground Two Bodies Found in Ruin of Maryland Mansion

Relatives described Don and Sandra Pyle as loving grandparents nicknamed “Pop-Pop” and “Dee-Dee,” respectively, who loved the Baltimore Ravens and Orioles, as well as traveling.

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Lexi and Katie Boone, pictured here, were believed to be in an Annapolis, Maryland, mansion with their grandparents, Don and Sandra Pyle, when it burned to the ground on Monday, Jan. 19, 2015.

In a statement released Thursday, members of the Boone and Pyle families thanked those who have offered them comfort but added, "Our loss demands time and quiet reflection to process these feelings. We ask that you respect our need for privacy.

"Life is fragile," their statement read. "Make time today to embrace your loved ones."

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Investigators are searching for the cause of a fire that spread throughout Don and Sandy Pyle's 16,000-square-foot home. Their granddaughter, Charlotte Boone, pictured here, is believed to have been in the house when the fire broke out early on Monday, Jan. 19, 2015.

Don and Sandra Pyle had spend the night before the blaze treating the children to a special night at the Medieval Times restaurant, according to a family spokeswoman. The couple also took the children to Target so they could get costumes before going to the restaurant.

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The children, including Wes Boone pictured here, were staying with their grandparents for the long weekend.

The fire is being handled as a criminal investigation, said officials. The U.S. Department of Alcohol, Tobacco, Firearms and Explosives also sent investigators.

ABC News' Emily Shapiro, Bazi Kanani, Dan Good and The Associated Press contributed to this report.