A Brooklyn fire that killed four people, including two children, and injured three others was the work of an arsonist who died in the New Year’s Day conflagration, according to officials.

“I don’t know what devil would do this, especially with three children sleeping in the room,” an in-law of one of the survivors, Jane Constantine, 70, said. “It had to be somebody crazy.”

Police identified the dead as Ribule Lemorin, 43, Nadege Viaud, 31, and her two children, Jeffrey, 5, and Bernard, 2. The four died of smoke inhalation, according to the chief spokeswoman of the medical examiner’s office, Ellen Borakove. The deaths were classified as a murder-suicide by Lemorin.

The Crown Heights fire, which occurred on the sixth floor of 901 Washington Ave. at 3 a.m., was ruled an arson yesterday, according to the fire department. The triple homicide marked the city’s first murders of 2005 and the highest body count of any homicide since an arsonist torched a Brooklyn apartment building on April 3, 2003, killing four people.

The survivors included Juni Gerard, 57, who was critically burned, according to family members, a 63-year-old man, and an 8-year-old boy, who were seriously burned, according to the Fire Department. Their names could not immediately be confirmed. All three were being treated at the Cornell Burn Center.

Joseph Gerard, 54, who lives on the fifth floor of the Washington Avenue building, wailed yesterday afternoon when he got a false call from a co-worker that his sister Ms. Gerard had succumbed from her wounds.

“She is my life,” Mr. Gerard sobbed as he was consoled by family members. But the caller was wrong. Mr. Gerard, a nursing-home dietitian, learned later that his sister was still alive.

Ms. Constantine said Ms. Gerard, a Haitian-born nurse, worked two jobs and helped other family members immigrate to America.

“She is good, from her head to her toes,” Ms. Constantine said. “She is the mother of everybody.”

The victims lived at the top floor of a brick apartment building overlooking the Brooklyn Botanical Gardens at Prospect Park. Neighbors initially thought the sounds of screaming from the apartment were from New Year’s revelry, not the agony of burning children, until the smell of smoke permeated the upper floors.

Gregory Cuyler, 50, a teacher who lives below the burned apartment, said he rushed upstairs to find Ms. Gerard in the hall with her clothes on fire.

“She was yelling, saying she was burning, she was in pain,” Mr. Cuyler said. “From the torso down she was burnt. I dragged her to the stairwell and that’s when the firemen came up.”

Mr. Cuyler said they carried Ms. Gerard downstairs. Mr. Cuyler’s girlfriend, Pauline Avent, 47, a schoolteacher, looked outside her fifth-floor apartment and saw Ms. Gerard lying in the hall.

“You could see where her skin was burnt,” Ms. Avent said. “You could her flesh, and her blood was all over the floor. She’s my neighbor and I didn’t even know who she was.”

The fire burned through a bedroom ceiling in the apartment of Mr. Cuyler and Ms. Avent but did not spread into the apartment itself. Slats of lumber hung from a hole the size of a doorway, and chunks of plaster littered the floor, the chairs, and the leopard-print bedspread.

Surveying the damage, Mr. Cuyler said: “At least I’m alive.”

The president of the Uniformed Firefighters Association, Steve Cassidy, blamed the Crown Heights deaths on a department-wide staff reshuffling December 2, resulting in a 20% reduction of firefighter crews.

Mr. Cassidy said the reduction resulted in four firefighters having to stretch a 500-foot length of hose up five flights of stairs at the building. He said the victims “did not get the adequate response to where they were, and that’s the result of Mayor Bloomberg’s and Scoppetta’s staff reductions,” Mr. Cassidy said.

Nicholas Scoppetta is the city’s fire commissioner.

In a prepared statement, the fire department said Mr. Cassidy’s comments were “completely without merit.”

“All the evidence points to the fact that a fifth firefighter on the first due engine would not have made a difference in saving the lives of these victims,” the statement said.

At 11:34 a.m. Saturday, just hours after the Crown Heights fire, a 19-year-old man was killed in a fire at Fresh Meadows, Queens.