Philadelphia's child-welfare agency has been scrambling to remake itself since an Inquirer investigation last fall explored a string of deaths of children under DHS protection.

DHS has undertaken a host of reforms, including new procedures to evaluate the safety of children. Its workers visit the most vulnerable children more often and has hired more nurses to spot medical problems.

In a tough report released four days before Leach's death, an expert panel appointed by Mayor Street said "significant system failures" at DHS had let children die needlessly.

In particular, the report criticized DHS oversight of the private agencies that receive millions of dollars to work with the city's troubled children.

Although Philadelphia has sent scores of teenagers to Chad, paying it $6 million in the last three years, city and state social workers failed to closely monitor how it was treating those children.

For example, in 2006, Pennsylvania child-welfare officials sent out a directive strongly discouraging restraint techniques except as a last resort.

Through a bureaucratic oversight, that directive was never sent to Chad. On Friday, state officials said they would make sure Chad got the message.

In Philadelphia, DHS officials struggled last week to explain why Chad continued to earn their approval, even as DHS's own inspectors filed reports that found the center consistently failed to meet many standards.

For example, one 2005 report said teenagers at the center had complained that staff members had improperly used physical force to restrain them. They also complained that staff members had sex with residents and watched pornography with them.

Before releasing it, the city censored that section of the report, saying it was related to the ongoing investigation and needed to be kept secret. The contents were confirmed by sources familiar with the document.

Throughout last week, DHS released confusing, contradictory and, at times, incorrect information about its dealings with Chad, particularly what it knew about the earlier death.

On Tuesday, Arthur C. Evans Jr., the acting DHS commissioner, said in a statement:

"We were not informed of the previous death. It was the Chad facility's obligation to inform DHS of the 2005 death, but they did not do so."

By Thursday, DHS admitted that was not true.

The agency reversed course after learning that a former Chad executive disputed its account. The executive said in an interview that he had flown to Philadelphia to brief DHS officials about the girl's death.

A source at DHS said on Friday that Evans was initially misinformed by a senior staff member.

Last week, Evans acknowledged failures in DHS's oversight but said a new system would provide "a much more accurate picture" of the quality of outside contractors such as Chad.

Steven Oakman heads the contracting office at DHS. "I'll have to refer you to the commissioner's office," Oakman said on Thursday. "All of the statements are coming out of there."

After Leach died, investigators descended on Tennessee, including teams from from DHS, Family Court, and the Philadelphia public defender's office.