Bertha Lee Brown was 20 days short of her 37th birthday when she died of suffocation at Forest Haven, Washington's trouble-plagued home for the mentally retarded.

Brown had been a resident of the institution for 30 years. She was designated "profoundly retarded," meaning that her mental development was lower than that of a 2-year-old child.

Brown was one of 428 such profoundly or severely retarded persons at Forest Haven. With two brothers who never visited her and a mother who is retarded, she was, like many of the 1,025 Forest haven residents, abandoned to the institution.

A number of other institutions for the retarded throughout the country have been closed down or have had their rosters sharply cut back in recent years. The reason, more often than not has been incidents like Bertha. Brown's death or yesterday's shooting of two residents and five employes.

People like Brown, their faces and bodies often cruelly deformed, their speech and motions infantile, banging their heads against a wall, laughing and babbling seemingly without reason, have for centuries been locked away from society's sight and mind in places like Forest Haven.

Their actions, so adorable in small children, become grotesque, frightening in children in adult bodies.

As is not unusual among very young children, Brown attempted to eat almost anything she could put her hands on. Thus, when she was left alone, bound to a toilet, before dawn on April 2, she bit through the socks and knotted sleeves that covered her hands and consumed her own feces - suffocating.

Nursing assistant Eva R. Sullivan, who left Brown "for 15 minutes" to deal with a fight that had broken out elsewhere in the ward, returned to the lavatory and found Brown on the floor, choking to death, according to hospital records. Revival efforts failed and Brown was declared dead on arrival at Prince George's County Hospital.

Brown's death and yesterday's shooting were the latest in a series of tragedies at Forest Haven, in Laurel, Md. The incidents have reopened intense, but largely unpublicized, debade over the operation and future of this institution and for 180 similar public mental health facilities throughout the United States.

Those who defend Forest Haven, like acting superintendent Fred Perry, insist that Brown's death could have taken place no matter where she was housed, "even if she were at home with members of her own family who loved her and watched over her every minute of the day and night."

"Who's to say?" Perry asked. "Maybe in time we could have turned her around. But the resources simply are not here. We're doing the best we can with what we have now."

Those who oppose Forest Haven and the concept of placing the retarded in insolated mass institutions insist that the atmosphere in these places forsters recurring incidents like Brown's death.

"Because of crowded conditions, lack of manpower and other short-cumings, places like Forest Haven contribute to abuse of patients by other patients as well as by staff members," said Fred Krause, executive director of the President's Committee on Mental Retardation. "I've worked eight years in institutions and I've seen how frustration leads to abuse."

Attracting high quality staff members is a severe problem. For example, despite intensive efforts to hire a physical therapist, Perry said, Forest Haven has been unable to attract a qualified applicant "and we should have two or three."

"It's not simply a matter of pay," said Nathanial Brooks, acting chief of Forest Haven's residential services division. "Unless a person has some inner drive, you just can't pay him enough to work here."

The Justice Department has called for all documents in Brown's case, although the department lawyers do not allege that Brown's death may have resulted from abuse.

Rather, according to Harry Fulton, chief of the mental health division of the D.C. Public Defender's Service, "the real argument should be over why she was left to rot out there for 30 years; why more time and money weren't spent in teaching her minimal skills."

Mental retardation specialists believe that pica, Brown's behavior disorder, can be markedly reduced or eliminated through behaviorial modification treatment. But such treatment, according to an official publication of the American Association on Mental Deficiency, "is difficult to maintain" in mass institutions like Forest Haven.

"In order to have adequate staffing in cases like Bertha Brown's," said Dr. James Boyland, chief medical officer of Forest Haven, "we'd have to have a ratio of one staff member to one resident, or one-to-two at least. And, of course, that's just not possible."

During most of Brown's life at Forest Haven virtually no effort was made to modify her bahavior, authorities at the institution said. Rather, whenever she "acted up," she was encased in a strait jacket-type of garment known as a "mummy." The files on Brown reported that she had become so used to the "mummy" that she habitually kept her arms crossed in front of her - even when it was removed.

About 18 months ago, when Congress approved a $4.2 million budget increase and Forest Haven began remodeling its buildings and hiring extra personnel, Shirley Rees became unit chief of East 2, the wing of the Curley Building where Brown was a resident.

"We removed the mummy and we began teaching her to use her hands and to walk and we started toileting her regularly so that she wouldn't soil her bed so often," Rees said in the bright yellow-painted cinderblock hallway of East 2.

"Because - for obvious reasons - we couldn't hope to modify her behavior with food reinforcement, as we do with other patients, we tried to reinforce her with love," said Rees. "We held her and hugged her whenever we could."

As she spoke, she gently disentangled a young woman's arms from around her neck. Awkardly, the woman made her way to a wall mirror, where she intermittently peered at her image and struck the glass with her hand.

Nearby, a staff member was urging four men and women, their heads deformed, their limbs twisted, to crawl through an open-ended cardboard carton. When they completed their tasks they were awarded with cookies, and they laughed.

Fred Cunningham, a detective with the U.S. Park Police, which holds jurisdiction over the federal preserve on which Forest Haven is situated, said he investigated Brown's death and is satisfied that there was no negligence by any staff member.

Cunningham said he found that, at the time of the death, three attendants were on duty in Brown's ward. Because of fourth staffer was on sick leave, one attendant was working overtime. The three staffers were in charge of 18 residents.

Nothing that he had previously conducted numerous investigations of "deaths, rapes and other abuses" at Forest Haven, Cunningham said:

"There is frequently a ratio of six or seven residents to one counsellor. This appear to be inadequate. I assume that under the D.C. budget they could have more staff. But that's not our job. We just investigate."

As is standard procedure in such cases, Cunningham said, he telephoned his findings to assistant U.S. Attorney Neil Janey in Baltimore, "The U.S. Attorney's office didn't want any written records because they decided that no further investigation was required," Cunningham said.

In response to repeated inquiries by The Washington Post, Janey made the following statement, "Mr. Baker [Acting U.S. Attorney Russell T. Baker] has authorized me to say that this office declined to make any further investigation or prosecution, based on the recommendation of the Park Police."

Julian Tepper, a Washington lawyer representing a Forest Haven resident who allegedly was beaten by a nursing assistant in 1975, said the Park Police were "totally unprepared" to cope with cases at the institution.

The case of Judy Atkin, whom Tepper represents, is to be heard in D.C. Superior Court on June 12. The person charged with beating Atkin, former psychiatric nursing assistant Mary Holloway, has been transferred from Forest Haven to the Emergency Mental Health Services division of the D.C. Department of Human Resources.

Transfers instead of dismissals of staff members accused of various kinds of abuse and negligence at Forest Haven are commonplace.

The alleged rape of another resident illustrates another problem. According to Cunningham who investigated the allegation, "I got lots of evidence. We had the guy dead to rights. But the girl was declared incompetent to testify and the U.S. Attorney at Baltimore did not prosecute."

The alleged assailant, has been transferred to another area of Forest Haven. "His behavior is being monitored," acting director Perry said, "but there is no substantiation of the allegation."

Since Forest Haven was built in 1925, there have been numerous scandals and outcries, several of them in recent years. In 1976, the late Sen. Hubert H. Humphrey became a champion of rights for Forest Haven residents and, partly as a result of his intervention, Congress approved $4.2 million to improve conditions and to increase the staff by 319.

Most of the additional staff members have been hired and most of the buildings have been refurbished. Maintenance standards have been improved. For example, the lavatories of the Curley Building, where Bertha Brown died, are immaculate, unlike conditions several years ago.

Profoundly retarded patients, who once were allowed to go naked or dressed in filthy diapers, are now, for the most part, kept fully clothed. Cooking and dining facilities have been improved vastly.

But a senior staff member, who asked not to be named, insisted that the improvements are mainly cosmetic. "There have been some improvements to the plant, no doubt," she said. "But the residents are getting no better care than before, maybe even worse, except for custodial care. Forest Haven is nothing more than a warehouse for retarded human beings.