Sullivan was part of a team that won a 2007 Casey Medal for their project.

In early September 2006, five months shy of her second birthday, Alayiah

Turman was pummeled to death after she interrupted her father’s video game. Reporter Ken Dilanian read the story on a Wednesday morning, then handed me the paper and pointed to the 21st paragraph. The city's child welfare agency had investigated complaints that Alayiah was being abused.

One day after Alayiah’s death, the director of the city's Department of Human Services said workers who had investigated the earlier claim had no reason to suspect abuse. The baby had looked healthy and, judging from the food in the cupboard, the home didn't look like an abusive one. She couldn't explain why an autopsy showed Alayiah had a healed fracture on her arm.

We wondered how many other children under the city's supervision had died from abuse.

In Pennsylvania it can be a tough question to answer. Child welfare records here are confidential and officials who disclose the identity of a child receiving services can go to jail, even if the child is deceased.

But we had a roadmap: As the paper's public health reporter, I had recently obtained a record of every death the city's medical examiner had investigated, the first time that information had ever been released.

That database gave us the name of every child who had died, and the cause of death. In a few cases, there were notes indicating that DHS had been monitoring the child.

As we searched newspaper clips, we found several stories about child homicides, mentioning without elaboration that DHS had been involved with the family.

With a small universe of cases, we turned to court files. If a parent had been prosecuted for killing a child, the parent’s interaction with child welfare authorities tended to creep into the public record.

Ken and I spent weeks sifting through those case files, and interviewing neighbors, police officers, lawyers, judges and advocates. The agency refused to answer questions about its decisions in the cases, but did release figures on how many children "known to the agency" had subsequently died.

On October 15, just one month after Alayiah's death, we published a 4,519-word account of DHS ineptitude. The story looked in detail at three cases where DHS ignored warning signs that children were in danger and the children ultimately were killed. And the story disclosed that although the agency had hired consultants to help better assess risk, the submitted reports were gathering dust, the recommendations never implemented.

A week later, a Philadelphia mayor, who loathed to react to public pressure, ousted the head of the child welfare agency and her deputy. He appointed an investigating commission and ordered safety checks on thousands of children receiving DHS services.

Meanwhile, tips came cascading into the newspaper, including one about Danieal Kelly, a 14-year-old with cerebral palsy who died of dehydration in a stifling attic room, even though DHS was paying an outside agency to visit her twice a week.

Reporters Craig McCoy and Nancy Phillips painstakingly examined that case in a story that prompted widespread outrage. In another follow-up, the team showed that the same contractor that botched the Kelly case was falsely reporting that it was monitoring a teen who turned out to be wanted for murder.

Melissa Dribben, a veteran features writer, was dispatched to tell the story from the perspective of caseworkers struggling under conditions most people couldn't imagine. She also profiled the new agency chief, the man brought in to turn things around.

In June, the mayor's investigating panel confirmed the findings of our initial stories and recommended that DHS make dozens of changes. The recommendations included that DHS make a public record of all injuries and deaths and the mayor create a public oversight panel to keep tabs on the reforms and the agency. There currently is a bill in the legislature that would allow counties to release details of a death or serious injury.

In the past year our team has written more than 30 follow-ups to the original investigation, including stories exposing lax oversight of contractors, a string of subsequent deaths of children under DHS care, and the agency's efforts at reform.

Most recently, after a Philadelphia teen under DHS custody died while being restrained at a Tennessee treatment center, Craig McCoy and I showed that for years the city had ignored complaints of abuse and overuse of restraints on youths at the treatment center. The city has since withdrawn all children from the facility.