D.C. Administrator Thomas M. Downs was harshly criticized last night at a Georgetown neighborhood meeting by residents who said the city had not disclosed its intention to buy a mansion to house mentally and emotionally disturbed children.

Speaking at an often-stormy Advisory Neighborhood Commission meeting, Downs defended the city's purchase of the Hurt Home for the Blind, at 3050 R St. NW. He said he moved swiftly after reading that the 32-room, three-story brick mansion was for sale in June, saying it is needed to house and educate 24 children.

"I did it," Downs told more than 75 Georgetown residents, many of them angered by the city's recent $2.9 million purchase of the home.

"The authority was there. The program need was there and the building was there," he said.

Later, he said there are about 600 group homes -- including adult halfway houses, youth homes and other facilities -- yet only "four or five" are located in wards 2 and 3. There is a "strict case of N-I-M-B-Y -- not in my back yard -- in Washington," Downs said.

But neighborhood residents, D.C. Council member John A. Wilson and commissioners did not accept Downs' reasoning and argued heatedly that Downs' office and the newly formed Commission on Mental Health Services had not clearly communicated their intentions to purchase the property nor fully informed the community of its intended use.

Commissioner John Wagley voiced worry about the effect of the group home on its neighbors. Although the home will be for youngsters 8 to 14, he noted that he has a 14-year-old son who is 5 foot 11. "I share the nervousness," he said. "Some 14-year-olds can be very terrifying."

The mental health commission is an umbrella organization for mental health services in the District that will assume the responsibilities of the Mental Health Services Administration when it begins operations Oct. 1.

The commission, headed by Robert Washington, has been made responsible by the federal government for speeding the deinstitutionalization of patients at St. Elizabeths Hospital, the city's mental care hospital, and reintroducing District children with mental disorders into the community.

Most such children now are separated from their families and attend school and live in such far-flung places as Massachusetts and Texas.

The mansion was endowed early this century as a home for the blind but in recent years was unable to maintain a full number of residents because of the increasing independence of blind people.

Washington and Downs said last night that city government had made the ANC members aware of its plans, but their audience accused the city of changing, as recently as yesterday morning in some instances, previously communicated specifications for the group house and going through with the purchase without the benefit of significant public comment.

Commissioner Rory Quirk, in rebuke to Down's assertion that the city had to act quickly after recently losing a bid to buy another suitable facility, said that "the letter and spirit of the law says come to the ANC and haste isn't an excuse."

One audience member, Dr. Donald Mitchell, denied Downs' assertion that Georgetown has only a small smattering of group facilities. He said the area is home to several schools, a boys club and two public parks, and he and others said there is no available parking for the group home's full-time staff members.