It was not immediately clear how the victims were related to one another.

Foster McPhee, 67, who lives in the neighborhood, said he was driving by when he saw smoke and flames pouring from the house and pulled over.

“The next thing I know, the firefighter’s coming out carrying a baby, and the baby was badly burned,” Mr. McPhee said.

He said firefighters also brought out what he thought were a young man and a woman. “I couldn’t really tell — they were burned so badly,” he said. “It was just horrible to see.”

The house was left a charred hull by the flames, which burned away much of its cream-colored siding. The fire also damaged one of the houses next door, Mr. Nigro said. The street, lined with small houses, most of them three stories tall, was cordoned off on Sunday evening, when the area was still crowded with firefighters and emergency workers.

It was an emotional scene as women cried and embraced in a yard across the street, beyond the police tape. Down the block, another man gently sobbed on the sidewalk. A woman ran up to the police tape, jumping and screaming, overcome with emotion. “Why would God let this happen?” she cried, repeating it over and over again.

“It’s not fair!” she said as others sought to console her. “We’re a God-fearing family. It ain’t right.”

The scene drew a crowd of neighbors, who stood along the police lines on a chilly, overcast evening. Some had known the family. “They’re very nice people,” said Gary Rhodes, who lives about a block away. “It hurts. It’s sad, man.”