A 3-year-old who suffered life-threatening injuries in a Roxbury home is now in state custody, authorities said Monday.

The child was brought to a hospital by first responders from a home on Alpine Street Sunday night, said Officer Rachel Maguire, a police spokeswoman.

But as neighbors wondered about the fate of a child few could remember seeing, details about the incident remained scarce.

In an e-mail, a spokeswoman for the state Department of Children and Families said Monday that the child was in the custody of the child-protection agency.

“The Department received a report on this situation and, as we investigate in collaboration with law enforcement, custody of the child has been transferred to DCF,’’ spokeswoman Andrea Grossman wrote in an e-mail to the Globe.

A second child who lives in the home was also taken into DCF custody.

The statement did not say if DCF was involved with the family prior to the arrival of police there Sunday night. A spokesman for the Suffolk district attorney’s office said he had no information about any charges.

Neighbors said the white, three-story house at the top of a hill had been home to a rotating cast of residents over the years, and furniture was routinely moved in and out.

The house’s owner, who neighbors said lives on the first floor, did not respond to calls and e-mails seeking comment Monday.

A neighbor who lives on the third floor of the house said the incident involved the family on the second floor.

He said he did not know the family or how long they had been there. He saw them only occasionally — he moved in recently, he said, and works overnight.

“I thought they were quiet people,’’ said the man, who did not give his name.

Police were inside the house much of the day Monday and brought in folding chairs late Monday afternoon. Caution tape was still strung across the driveway.

Police said the investigation was continuing.

John R. Ellement of the Globe staff contributed to this report. Nestor Ramos can be reached at nestor.ramos@globe.com. Follow him on Twitter @NestorARamos.