Investigators plan to wrap up their investigation of the Christmas fire that killed three girls and their grandparents by the end of next week, a police official said.

"We still have some more interviews to do," Capt. Richard Conklin said Wednesday evening. "Hopefully, by the end of next week, we might come back with something."

Wednesday was the one-month anniversary of the fire that killed Lilian Badger, 9, 7-year-old twins Sarah and Grace Badger and grandparents Lomer and Pauline Johnson. The girls' mother, Madonna Badger, an ad executive in the fashion industry, and her boyfriend, Michael Borcina, escaped.

Borcina had been doing work at the $1.7 million house next to the Long Island Sound, which was razed after the fire out of safety concerns.

The fire is believed to have been caused by embers that had been removed from the home's fireplace. Borcina reportedly put the ashes in a bag and placed it in a back room so the children would not worry about Santa Claus coming down the chimney.

Fire officials have said it appears there were no working smoke detectors in the house.

Conklin declined to talk about what investigators have learned so far. They have re-interviewed Madonna Badger and Borcina, he said; they had initially been interviewed the day of the fire.

Based on the information investigators received in the recent interviews, they now have follow-up questions to ask, he said.

Stamford Lt. Diedrich Hohn said in an e-mail Thursday that the only contact police have with Badger is through her lawyer, Stanley A. Twardy Jr.