There always will be deaths that child-protection authorities could not have foreseen or prevented. And the agency is in much better shape than two decades ago, when a class-action lawsuit forced it to improve.

But experts who consulted for DHS in recent years told The Inquirer that the agency's system for evaluating risk is inadequate. They said the agency still had not addressed key failings uncovered after Porchia Bennett's death.

"Their investigators are not being given a policy for how to make decisions or an understanding of what risks can be tolerated," said Gelles, a former DHS consultant who became so disillusioned that he now serves as an expert witness for lawyers suing the agency.

Mayor Street, walking into City Hall yesterday to attend a chess lecture, declined to answer questions about the performance of his human-services department.

"I don't have any comment," he said. "I don't have any comment on that at this time."

In the three cases with the most extensive public records about the department's actions, an Inquirer review of court documents and interviews with relatives and neighbors found that people had concerns about the children's welfare before they died - red flags that could have been apparent to inquiring caseworkers.

Five other cases, where there is less public information about DHS actions, raise questions about whether the agency could have done more to prevent the deaths. The Inquirer examined only cases in which the agency's involvement could be determined from other sources, because DHS would not disclose which of the dead children it had checked on.

The Inquirer found:

In the Bryanna Redmond punching death, the toddler was killed after the agency closed a case involving her mentally disabled mother, who had talked of abandoning the baby at birth. A grandmother testified in court that she had asked DHS for help, to no avail.