Two more bodies were found in the wreckage of a mansion in Annapolis where six people are believed to have died, authorities said on Thursday.

Anne Arundel County fire officials said Thursday that investigators have now found the remains of four people since the fire on Monday, and that all four would be autopsied and identified by the Office of the Chief Medical Examiner in Baltimore.

Relatives of the family have released a statement identifying six family members whom they believe died in the house fire at an Annapolis mansion known in the neighborhood as “the castle.”

The statement confirmed that fire officials have been searching for Don and Sandra Pyle along with their grandchildren: Alexis (Lexi) Boone, 8; Kaitlyn (Katie) Boone, 7; Charlotte Boone, 8; and Wesley (Wes) Boone, 6. Lexi and Katie are the children of Randy and Stacey Boone. Charlotte and Wes are the children of Clint Boone, 37, and his ex-wife, Eve Morrison, 39.

A fifth grandchild is a newborn boy who remained at home with his parents, Randy and Stacey Boone, a spokeswoman for the family said. Randy, 38, and Stacey, 34, live about 15 minutes away from the Pyles.

The four oldest children, all students at the Severn School in Severna Park, were at a sleepover with their grandparents Sunday night because Monday was a holiday, the family spokeswoman said. They’d gone to Target on Sunday to buy the children costumes for a visit to Medieval Times at the Arundel Mills mall. Don and Sandy took the kids to eat dinner and watch knights jousting in a banquet setting before heading back to their own castle, as the Pyles’s massive 16,000-square-foot house was known to their neighbors.

In a message to her friends on Facebook on Tuesday, Stacey Boone said: “I never knew that I could hurt this badly. It’s unreal. All one big nightmare that I can’t wake up from.”

Anne Arundel Fire Capt. Russell Davies Jr. said that after the second day that crews have entered the mansion’s ruins, they still have not found clues indicating what started the fire, or whether the fire was an accident or foul play was involved.

“Until we make a determination one way or another, it’s going to stay a criminal investigation,” said Davies, who added that handling the scene as a criminal investigation is standard procedure to preserve evidence in the event a case needs to go to court.

Special Agent Dave Cheplak, a spokesman for the Baltimore office of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), said investigators deployed an “accelerant dog” at the scene for the first time Thursday.

The dogs are trained to detect the smell of gasoline and other materials that may spark fires in the same way canines are trained to detect explosives, Cheplak said. The dog could also help pinpoint where the fire started and why.

He said that he could not comment on whether the accelerant dogs made any positive hits, but did say cadaver dogs deployed at the scene were instrumental in helping crews determine where to dig as they search for bodies.

“We’re definitely making progress in terms of determining the cause and origin [of the fire] based on the physical evidence we’re recovering, as well as through the series of interviews we’ve received from the team,” Cheplak said.

The ATF has also been deploying specialty software that provides “forensic mapping,” allowing investigators to reconstruct a building’s structure down to where a couch might have been placed or where drapes may have hung, Cheplak said.

“Anytime you have a family of six people killed in a home, it’s certainly not common place,” Cheplak said. “Nobody is taking it as routine.”

On Wednesday, two bodies were found in the mansion owned by Pyle, 56, chief operating officer of Northern Virginia-based ScienceLogic, and his wife, Sandra, 63.

On Thursday morning, a spokesman for the family released a statement acknowledging the outpouring of support they’ve received and hinting at their devastating grief:

“On behalf of the Boone and Pyle families, we wish to express our gratitude and appreciation for the love and support being shared with us during this tragic event. We are blessed that so many family, friends, and neighbors have come together for us in our time of need.

“We recognize the dedicated efforts from Anne Arundel County Fire and Police Departments, the Naval Academy, the Bureau of Alcohol, Tobacco, and Firearms, and other first responders. We want our community to know how proud we are of all who have helped us.

“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. Make time today to embrace your loved ones.”

Senior Deputy State Fire Marshal Bruce Bouch called the blaze in Annapolis one of the “most devastating” fire-related incidents Maryland has seen in years. The Maryland State Fire Marshal has been helping Anne Arundel County with its investigation.

The county’s deadliest residential fire on record occurred on April 23, 1961, when nine family members were killed in a blaze in their Rose Haven home, Davies said.

The fire ripped through the Pyles’ mansion, which was constructed with turrets to look like a castle, in the wee hours of Monday morning, burning it to the ground.

Bouch said an alarm had alerted 911 that smoke was detected on the first and second floors of the home, early Monday, but because of vast open space in the mansion, the fire likely spread quickly and “overcame the space.”

“By the time the fire service was on the scene, they already had a raging, out of control fire they had to fight,” Bouch said.

Fire sprinklers will become mandatory in all new residential buildings in Maryland starting June 2015. He said had they been in the Pyle’s home, “there probably wouldn’t be a story today.”

Crews found the remains of two bodies Wednesday, but four others are still missing, said Davies at a Wednesday news conference, where he was joined by the Anne Arundel county executive, fire chief, police chief and state’s attorney, as well as officials from the ATF and the state fire marshal’s office.

Davies declined to say whether the remains discovered belonged to the children or adults or where the bodies were found.

Crews will continue to sift through the wreckage, which still held hot spots more than 48 hours after 80 firefighters battled the four-alarm blaze. “There is still a lot of work to be done,” Davies said. “This is a massive effort and will take days to complete.”

Authorities said earlier that they were conducting an “active criminal investigation,” although they did not have any reason to believe that the fire was suspicious. Davies repeated on Wednesday that it was too early to tell whether foul play was involved.

The Pyles built the elaborate home on an eight-acre property on Childs Point Road in 2005. They loved to entertain there, hosting fundraisers and family parties. Many of the parties revolved around the Baltimore Orioles and the Baltimore Ravens.

Don Pyle, who grew up north of Baltimore and played lacrosse at the University of Delaware, was an avid sports fan. In September 2013, when the Delaware football team traveled to Annapolis to play Navy, the Pyles hosted an event for alumni and school leaders, said Bob Shillinglaw, the longtime head lacrosse coach at Delaware.

“Just an unbelievable, gorgeous house,” said Shillinglaw, who described the Pyles as “very friendly people. Very genuine.”

The couple met when they both worked at Rixon in 1981, said Nick Whelan, who had an engineering job at the Silver Spring, Md., tech company. Sandy worked in marketing, and Don was in sales.

In an interview with The Washington Post in October, Don Pyle described Rixon as “a company that connected computers over transmission lines and that company was the foundation of companies that started designing equipment to connect computers together.”

His work there became the foundation of his fortune and the foundation of his family.

He and Sandy married about five years after they met, Whelan said, and Don became stepfather to Sandy’s two young sons, Clint and Randy Boone. Together, the sons had given the couple five grandchildren, whom they treasured.

The four oldest children went to the private Severn School, where tuition for elementary students runs nearly $18,000 a year and where the family was such a fixture that one of the parking spaces was marked “Reserved for Pyle family.”

The Pyles’ friends were struggling to absorb what had been lost in the fire.

“All of us are numb. It’s just hard to talk about,” Shillinglaw said. “For someone as wealthy as [Don] was, he’s the most down-to-earth person I ever met. He treated everyone like long-lost buddies, like great friends.”

John Woodrow Cox, Joe Heim and Julie Zauzmer contributed to this report.