On a morning in mid-December, a man moving his truck found a dismembered body behind a dingy boardinghouse on Kennedy Street NW.

There were 262 homicides in Washington last year, but this one stood out as among the most gruesome. The victim had been beaten about the head and body and slashed in the throat. Both his legs had been severed.

Three weeks later, police charged 60-year-old Joseph D. Hilliard, a former tenant of the boardinghouse, in the slaying and moved him to St. Elizabeths Hospital, the psychiatric facility in Southeast Washington.

For Hilliard, the hospital was a very familiar place.

Hilliard was first admitted to St. Elizabeths in 1974, when he pleaded not guilty by reason of insanity to another murder charge. A paranoid schizophrenic with the gift of charm, he has never been released. But he has escaped a dozen times.

All told, Hilliard has spent more than eight of the past 29 years away from St. Elizabeths. Once, he went to California and got married. After another escape, he went to Pennsylvania and was convicted of throwing a woman from a window.

Despite his history, Hilliard was allowed by St. Elizabeths staff to walk around the hospital grounds alone in 2001. In December of that year, he escaped again. Then he allegedly did something he had never done in the previous 11 escapes: kill.

Police found Hilliard in blood-stained clothing three days after the slaying at the boardinghouse. The victim, 51-year-old David E. Edwards, had just moved into the basement of the house. At the time Edwards was slain, Hilliard had been on his own for one year and four days.

St. Elizabeths officials said that when treating the mentally ill -- including the criminally insane -- it is necessary to extend patients small freedoms in the hope that they will adjust and eventually be able to reenter society. They said that unaccompanied grounds privileges, like the ones Hilliard had the 12th time he escaped, are considered a valuable part of therapy, a step toward the real world, if the patients are ready for them.

Hilliard is by no means the only person to escape from St. Elizabeths, which has about 500 patients. Roughly 200 of its patients are people who were committed because of criminal cases, known as forensic patients, including John W. Hinckley Jr., who shot President Ronald Reagan and three others in 1981.

D.C. police files indicate that 22 patients were reported missing from the hospital in the last four months of 2002. That's as many as went missing in all of 2002 from Virginia's Eastern State Hospital in Williamsburg, which is about the same size.

Some city officials and mental health specialists questioned how St. Elizabeths let Hilliard get away again.

"Wow. It's hard to believe that after [the] escapes, he was given an unaccompanied grounds privilege," said Harold J. Bursztajn, a professor of psychiatry at Harvard Medical School. "If you leave someone unaccompanied when there's a potential of escape, you're not providing the most adequate care."

"This," said D.C. Council member Adrian M. Fenty (D-Ward 4), "is egregious incompetence."

The first killing tied to Hilliard took place more than 30 years ago.

Court records say that Hilliard, who is originally from Fayetteville, N.C., pulled a knife on Billy Boy Everette there in December 1972, and then took Everette's wife, Estherine, with him to Washington. Hilliard and Estherine Everette lived in the 200 block of N Street NW for much of the next few weeks. On Jan. 19, 1973, they had a fight, and 12 days later, Estherine Everette was found dead in an abandoned house nearby, with a stab wound to her chest, court records say.

Hilliard fled to Florida, where he was arrested and subsequently entered a plea of not guilty by reason of insanity. The court accepted his plea. In 1974, he was sent to St. Elizabeths, whose sprawling campus was then run by the federal government.

His first escape in 1976 lasted less than a month; Hilliard returned to St. Elizabeths voluntarily, court records say. Later that year, he escaped again. The back-and-forth continued in 1977, when Hilliard left the grounds two more times. In 1978, Hilliard escaped yet again and went to Pennsylvania, where court records say he was charged with aggravated assault and served about three years of a prison sentence. He was returned to St. Elizabeths upon his parole from Pennsylvania in 1982.

He didn't stay long. In 1983, he escaped again. This time he was gone eight months, during which he met and married a Nicaraguan woman in California.

Court records indicate that St. Elizabeths officials were concerned about the problem of his escaping. "He has resided on every level of security . . . [and] has held grounds privileges, only to escape or be found in possession of drugs and thereby return to maximum security and restart the cycle," Department of Health and Human Services officials wrote in 1987.

The D.C. government took over St. Elizabeths in 1987 but was unable to break the pattern. Hilliard's escapes continued: 1988, 1994, another in 1994, 1995 and 1999.

Hilliard's cousin Catherine Johnson expressed surprise when told that he had been at St. Elizabeths for a 1973 slaying. He had told her he was in St. Elizabeths for having too many traffic tickets and fake identification papers, she said.

"He didn't ever [say] anything about murder," Johnson said of the 1973 killing.

She said Hilliard often called her from such places as Las Vegas, and she sometimes saw him in their home town of Fayetteville. Once, she said, he came home with a Cadillac and said he had become a car salesman.

"He's been out of St. Elizabeths probably more than in it," said Johnson, a schoolteacher in Fayetteville. "He kept leaving, and I don't think they do any looking for him when he leaves."

She said Hilliard, whose criminal record dates to 1959, started to show signs of being erratic before he dropped out of high school. Still, she said, he can be quite charming and usually has no trouble convincing people to help him.

About two years after Hilliard returned from his 11th escape in 1999, court files say he had unaccompanied grounds privileges at the hospital. Hospital officials declined to say what led the Inpatient Services Division Review Board to approve those privileges.

On Dec. 9, 2001, Hilliard set out for the chapel by himself at 9 a.m.

He did not return.

That afternoon, Hilliard was reported missing to D.C. police. A warrant was issued for his arrest, and his case was referred to the U.S. Marshals Service based at D.C. Superior Court. Marshals declined to comment on the case. An official said that marshals look for St. Elizabeths escapees as they would for other fugitives.

St. Elizabeths officials said Hilliard was deemed ready for another chance, despite his escapes.

"If you elope, we don't hold it against you for the next 20 or 30 years," said Joy Holland, chief executive officer of the hospital, using the mental health system's term for escapes: "elopements."

"You have no choice but to look at how an individual is progressing," Holland said.

St. Elizabeths officials said they were required to give Hilliard an opportunity to progress. They said the law requires they move patients to the least restrictive setting under which they can be safely and effectively treated.

Other mental health specialists talked about the difficulty of finding the right balance for treating -- and securing -- the criminally insane.

If all hospitals simply locked up their forensic patients, "you'd have thousands and thousands of prison forensic beds" for criminally insane patients, said professor Joel Dvoskin of the University of Arizona medical college. "And somebody's got to pay for that."

Robert Keisling, a former D.C. mental health official, said that St. Elizabeths patients often escape after they are allowed "on-grounds" privileges, since guards don't stop them from walking out the gate.

"Once they get privileges to get out of the ward, there's basically nothing keeping them on the grounds," said Keisling, former director of the emergency psychiatric center, who left the government in 1999.

Linda Grant, a spokeswoman for the department of mental health, declined to say if Keisling's description was accurate. She pointed out that forensic patients accounted for 12 escapes in all of 2002. That's down from 27 four years ago, she said.

Sometime last year, Hilliard began living in the basement of the unlicensed boardinghouse in the 600 block of Kennedy Street. Though the house's owner declined to comment, two tenants said they believed Hilliard was not paying rent.

Hilliard sometimes threatened them and told them he had escaped from St. Elizabeths and had killed before, the tenants said.

The tenants, who asked not to be identified because they are witnesses in the criminal investigation, said David Edwards -- whom they called "painter man" because he worked on painting jobs -- was supposed to move into the basement Dec. 12. That evening, one of the tenants said she heard Hilliard talking outside.

"If I can't live in the basement, whoever lives there, I'll kill the [expletive]," she recalled Hilliard saying. Later that night, one of the tenants said she heard sawing.

The next morning, Edwards's body was found in the back yard. A few days later, police found Hilliard back at the house, wearing clothes covered in blood, according to charging documents.

City mental health officials would not comment on Hilliard's current security arrangements at St. Elizabeths. He is awaiting a preliminary hearing in D.C. Superior Court.

Tenants on Kennedy Street NW said last month they were frightened he would escape yet again and return to their home. "He said he was going to come back and kill everybody in here," one of the tenants said. "You got people walking the halls with hammers and sticks."

St. Elizabeths officials say it is necessary to extend patients small freedoms in the hope that they will adjust and eventually be able to reenter society. JOSEPH D. HILLIARD