A Brooklyn mother is in police custody in the beating death of her young son, yet another case raising troubling questions about the city's Administration for Children's Services and its ability to protect at-risk kids. NY1's Jeanine Ramirez filed the following report.

Zarah Coombs faces a murder charge in the death of her 4 year old son Zamair Combs. According to police, she admitted to beating the child with a stick, bruising him and leaving him unconscious.

A neighbor says the mother showed no emotion when emergency responders arrived Wednesday night. 

"She just standing there, like, watching like a bystander," the neighbor said. No one even know who the mother was because she wasn't screaming or nothing like that. Usually when something happens to somebody's child they're crying."

The 26-year-old mother is also charged with manslaughter, endangering a child and criminal possession of a weapon. 

Her two younger children, a toddler and a baby, were removed from home by the NYPD's Special Victims Unit. 

Family members say they didn't see any signs of abuse on the children, but they claimed that Coombs drank a lot. 

"When I got the call last night, it, my whole thing was just to get here and to pray that this young child makes it," said one family member. "Unfortunately, it's a tragedy right now, and as I said, if she's responsible, she has to be held accountable."

Police also spent hours Thursday questioning Zamair's stepfather, but he has not been charged with any crime.

Community members call the incident a tragedy. 

"It's sad. It's sad," said one community member.

"She should've reached out," said another. "If she was feeling like she needed help, she should've reached out."

The case is the latest in a series of troubling deaths raising questions about the city's child welfare agency, the Administration for Children's Services. On Thursday, a blistering report by the Department of Investigation faulted ACS in the tragic death of 3-year-old Jaden Jordan last fall.

In the case of Zamair Combs, ACS made visits to the home in the past, but details on that case history were not immediately available. DOI said it also would investigate his death.

The Administration for Children's Services says it's conducting its own investigation. An autopsy on the boy's body is underway.