District Mayor Anthony A. Williams yesterday fired five top managers and suspended two others at the troubled D.C. agency that deals with the mentally retarded, the first steps in what officials say will be a dramatic reorganization affecting agencies throughout city government.

Williams has told aides that he wants to "blow up" the system designed to serve the city's mentally retarded residents, starting with the Mental Retardation and Developmental Disabilities Administration. He plans to follow that with changes in five more divisions in the Human Services or Health departments, government sources said yesterday.

Williams's administration has been investigating the mental retardation agency since last month, when The Washington Post reported that far more mentally retarded wards who lived in the city's group homes had died in the District's care than the Department of Human Services had previously acknowledged.

Since 1993, not one of the 116 deaths in homes for the mentally retarded had been investigated. In addition, a former Human Services caseworker admitted to shredding documents concerning a problem death after The Post asked questions.

A report on the administration's investigation, to be released at a news conference today, says that "the entire mental retardation and developmental disabilities service delivery system . . . is incapable of providing quality service."

The management and oversight of D.C. employees and private-sector providers who work with the mentally retarded has been "inadequate," communication throughout the system is "ad hoc," fiscal matters have been neglected and the service delivery system must be "redefined," the report says.

"The system is highly dysfunctional and unable to execute its mission at its most basic level through its current structure and procedures," the report adds.

Government sources indicated yesterday that more firings are likely. Another victim of the mayor's investigation likely would have been Human Services Director Jearline F. Williams, who last week took an extended medical leave and then submitted her retirement papers.

Sources said yesterday that Williams, a longtime city employee and the Human Services chief for the past two years, "would not have survived" the mayor's investigation of her department, which includes the mental retardation agency.

After a series of reports in The Post last year, the FBI, D.C. police, the D.C. inspector general's office and the U.S. Justice Department also began investigations into the city's group home system and the scores of unreported deaths in the homes. Those investigations are continuing.

The officials Mayor Williams fired yesterday include Viola Keyes, who had been on administrative leave as the inspector general examined allegations in The Post that she had ordered the shredding of dozens of files concerning the dead in group homes.

Frances Bowie, a 29-year city employee who is a former director of the mental retardation agency and more recently has been a senior policy analyst with Human Services, also was sent a termination letter.

Bowie told The Post in March that no autopsy had been performed on one mentally retarded man who died in a D.C. group home because his two sisters had refused to grant permission. Bowie's staff said the sisters, whom they would not identify, were Jehovah's Witnesses and had religious objections to an autopsy.

The Post located the man's sisters, one a Baptist and the other a Catholic; each said no city or group home official had ever asked them about an autopsy. Human Services officials now acknowledge that they have no evidence to support their previous assertions that the women blocked an autopsy.

The mayor also fired longtime Human Services official Charles Hubbard, the director of the Bureau of Case Management. Before helping to run group home programs, Hubbard was the administrator of the Forest Haven asylum, which was shuttered by federal court order in 1991 after Justice Department investigators turned up evidence of dangerous conditions and widespread medical neglect.

Gordon Barrow, director of the Clinical Services Division at the mental retardation agency, also was fired yesterday, as was Pam Campbell, the agency's director of case management.

Last month, one of Campbell's former employees, Dwayne Franklin, told The Post that he had shredded documents regarding a troubling death in a group home. He said that Campbell and other supervisors rewarded staff members for covering up problem deaths and cases of neglect.

Two other managers were put on administrative leave yesterday, pending further investigation: Charles Howard, the mental retardation agency's acting director of program operations, and Karen Whittington, director of the contracts division.

"There has been and continues to be a lack of managers with solid management skills," the administration's report says.

The report also found that training programs and requirements are nearly nonexistent for staff members in the mental retardation system. Each organization in the system operates "in nearly complete isolation from the other," the report found. " . . . The service delivery system is broken."

The mayor has hired a new director and chief operations officer for the mental retardation agency. Meanwhile, staff members from other agencies will be detailed to the mental retardation agency, sources said. Deputy Mayor Carolyn N. Graham will use outside contractors to help rebuild the agency.

"Goodness, he's cleaning house from the top down," Robert Downs, who heads the Arc of the District of Columbia, the city's largest advocacy group for the developmentally disabled, said of the mayor. "That's what he needed to do. It may mean better days ahead for the persons who can't speak for themselves."

Elaine Patico, who kept a wrenching diary of the suffering of her brother, Peter, before he died in the group home system, was more guarded. Previous promises of change, she noted, have gone unrealized. Still, she views the mayor's actions as a beginning.

"People like my brother may finally get the care they need."

Staff writer Katherine Boo contributed to this report.

To read complete Post coverage of group homes and to see documents gathered by The Post, go to www.washingtonpost.com/invisible.