A service is planned for next week at the Campbell Funeral Chapel on the Upper East Side.
The remains of the home on Shippan Avenue were carted away on trucks.
Those interviews will be crucial in determining just what happened.
The only time they talked with authorities was the morning of the fire.
Meanwhile, an uncle of three girls killed with their grandparents said Wednesday that family members are devastated by the tragedy but comforted by each other and an outpouring of public sympathy.
Campbell Badger said that his brother Matthew Badger was devoted to his daughters. He says their family appreciates the prayers and support it has received.
"Matthew is devastated," Campbell Badger said Wednesday. "He's doing as best as can be expected under the circumstances."
Matthew Badger hasn't commented publicly since 10-year-old Lily and 7-year-old twins Grace and Sarah died of smoke inhalation along with their mother's parents, Lomer and Pauline Johnson.
Lomer Johnson also suffered a blunt head and neck trauma, which could have resulted from a fall or being hit by an object, according to the medical examiner.
Matthew Badger and Madonna Badger are divorcing, and he was not at the home when it was engulfed by flames.
Authorities say embers in a bag of discarded fireplace ashes started the blaze.
Madonna Badger, an advertising executive, escaped from the fire, as did Borcina, a friend and contractor working on the house. Borcina was released from a hospital on Wednesday morning, a spokeswoman said.
As flames shot from the three-story home, Madonna Badger climbed out a window onto scaffolding, screaming for her children and pointing to the third floor.
Firefighters went into the house twice trying to rescue the victims but were forced out by the blaze's intensity.
Borcina and Lomer Johnson, a department store Santa Claus who spent a long career as safety and security director for a Louisville, Ky.-based liquor company, tried to save them, as well.
One of the girls, found dead just inside a window, had been placed on a pile of books, apparently so Johnson could reach in and grab her after he jumped out.
Instead, authorities say, Johnson fell through the roof outside the window and was found dead in the rear of the house. He and his wife, both of Southbury, had been visiting their daughter for the holidays.
A Badger family and Johnson family statement issued by Madonna Badger's brother on Wednesday night said they wanted to express their thoughts and prayers for the people who've been "so deeply impacted by the tragedy on Christmas morning."
"We also want to say thank you for all of the prayers and well wishes that have come in from around the country and the world," said the families' statement, released by Wade Johnson. "We can feel the warmth of your prayers surrounding us as we struggle to cope with the tragic loss of our family members."
The Department of Consumer Protection said its records show neither Borcina nor his company, Tiberias Construction Inc., is currently registered to perform home improvement work in Connecticut. Registration is required by state law and provides certain contractual rights to the consumer, according to the department.
"We do not yet have enough information about what work was being done or had been completed," the agency said. "We will address the pertinent regulatory issues in due course."
Repeated attempts to contact Borcina by telephone since the fire killed the children and their grandparents have been unsuccessful.
Campbell Badger said his nieces were "wonderful, delightful energetic children."
"They were loved tremendously by their mother and their father, who always put their kids first," he said.
He said his brother, a television commercial director who lives in New York, was involved in all aspects of his daughters' lives and played all types of games and activities with them, including soccer, rollerblading and painting.
He said the Johnson and Badger families are grateful for the public support, which has included floral bouquets, stuffed animals and candles left by passers-by at the site of the torn-down Victorian home.
"We are really touched," he said. "Everyone wants to help in any way they can. We feel it, and it's remarkable."
(The Associated Press contributed to this report)
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