Service scheduled Thursday for 3 sisters killed in Christmas Day fire

NEW YORK (CNN) -- Mourners are expected to gather Thursday during a public funeral service in Manhattan's St. Thomas Church to pay their respects to three young girls who died in a house fire in Stamford, Connecticut, on Christmas Day.

The hour-long service is scheduled to start at 10:30 a.m. ET, according to the church website.

The family of Lily, 10, and 7- year-old twins Grace and Sarah Badger -- who died in the fire along with their grandparents, Lomer and Pauline Johnson -- held a private service on Wednesday.

The fire, which broke out around 5 a.m. Christmas Day in a three-story Victorian home, is believed to have been caused by smoldering embers removed from a fireplace, according to Stamford Chief Fire Marshal Barry Callahan.

Authorities said that Lomer Johnson fell through the roof rafters outside a window. One of the children's bodies was found just inside the window.

It appeared that Johnson was trying to get the child out, but died after climbing through the window, said acting Fire Chief Antonio Conte. The medical examiner's office said Johnson suffered from smoke inhalation in addition to trauma from the fall.

The girls' mother, Madonna Badger, and a friend escaped the blaze.

CNN affiliate WFSB reported that Badger attempted to climb the renovation scaffolding outside the home in an apparent attempt to reach her family.

Authorities said it was unclear whether the home had working smoke detectors.

The city of Stamford later razed the three-story home, which was under renovation, after determining it was unsafe.