MILWAUKEE -- A 1-year-old baby has died from what Milwaukee police said appears to be physical abuse.

Baby Boy Dies
Aunt Could Face Charges In Death Of One Year Old

Police responded to a 911 call from a home near 12th Street and Manitoba at about 6:15 p.m. Monday after a foster mother called to report she had killed a little boy.

They found the Christoopher L. Thomas in bed lifeless.

Police said Christopher was taken to an area hospital with critical injuries. He died Tuesday morning of head trauma.

Police found the boy's 2-year-old sister at another relative's home Monday night. They the girl's injuries also suggest ongoing abuse -- scarring on her upper body and face, scalded feet and she's unable to use her arms and legs.

Police said the Bureau of Milwaukee Child Welfare placed the boy and his sister in foster care with an aunt. The state took the children from their mother earlier this year after allegations of abuse, police said.

Late Tuesday afternoon, the agency issued this statement:

"With the police department, medical examiner and other authorities, we are investigating this tragic incident. When we learn all of the facts surrounding this situation, we will take all necessary and appropriate action."

A 24-year-old woman is currently in custody. Police said she is Christopher's aunt. She has no criminal record.

Prosecutors will wait for Wednesday's autopsy results before reviewing the case for possible criminal charges.