Since entering a witness protection program, three young women who saw a fatal shooting in a Bedford-Stuyvesant schoolyard in 2001 have had Brooklyn prosecutors in a bind, straining the lawyers’ patience and pushing the limits of the program.

The three women, who prosecutors have requested be identified only by their nicknames, have screamed at their protectors and demanded more money for food, housing, and other expenses.

They have been ejected from hotels where they are supposed to hide quietly, and they have visited neighborhoods they are supposed to avoid.

They have asked for – and received – rides to obstetrician appointments, and special deliveries of laundry money.

Difficulties came to a head recently when one of the three, Mookie, was charged with assault for allegedly slashing her boyfriend’s face with a piece of glass.

Despite their behavior, however, Mookie, Naia, and Quanna, who all lived in Bedford-Stuyvesant and who all are in their early 20s, remain under the protection of District Attorney Charles Hynes’s office.

“We’re wedded to them,” observed one member of the DA’s staff. “They’ve got us over a barrel.”

The women were crucial witnesses in prosecutors’ efforts to convict Dupree Harris, 30. The authorities say Harris, who is known as “Turf,” waged a campaign of intimidation and even murder to keep witnesses out of court. Based on the trio’s testimony, Harris was convicted last summer of bribery in connection with the schoolyard slaying – a slaying prosecutors alleged, but never proved, was done at Harris’s command.

The young women testified they were warned “to lie or die.”

For prosecutors, the women have posed a different quandary.

Another witness to the schoolyard slaying, Bobby Gibson, was killed in June 2002 just before he was to testify against the accused shooter, Harris’s half-brother, Wesley Sykes. Sykes was convicted of murder.

Since Gibson’s death, the case has played out in a public spotlight and led to a multimillion-dollar lawsuit against the DA’s office by his family.

Prosecutors have had to choose between swallowing their reservations about the women and risking disaster by removing them from the program.

Mr. Hynes’s office vows that, as with any witness, the women’s protection will never be cut off as long as they are in danger.

“You take your witnesses as you find them,” said Mary Faldich, assistant counsel to the district attorney. Ms. Faldich, who oversees the office’s witness protection program, said it would be “reprehensible” to abandon the women now. “Obligations are terminated when people are safe,” she said.

Harris’s lawyer, Stacey Richman, said prosecutors have been putting up with anything to secure a conviction against her client, who she insists is innocent.

“These are some savvy girls,” Ms. Richman said. “Once they figured out how to work the system, they were treating the DA’s office like a social service agency.”

The story behind Harris’s conviction has dragged prosecutors into the lives of three uneducated, young women – two of whom are single mothers – who constantly need help. Court testimony and documents obtained by The New York Sun offer a rare glimpse into the difficulties prosecutors have faced.

Protecting witnesses in the cases stemming from the schoolyard slaying has cost the office $230,000, including $114,000 spent to protect the three women. It has been the office’s most expensive protection effort in recent memory. In all, the office spends an average of $550,000 a year on witness protection and relocation. The sums do not include the DA’s office’s personnel costs.

Difficulties with witnesses in state and federal protection programs are not uncommon. At least in New York City, however, the programs face the additional burden of being underfinanced and largely ad hoc. Witnesses often want to return to their homes or contact people they shouldn’t.

“It’s hard for people to change their ways or pull up their roots,” the chief assistant district attorney for the Manhattan DA said. The Robert Morgenthau aide, James Kindler, said the only line a witness cannot cross is to commit a crime.

A prosecutor in Queens, Mike Mansfield, said his office stops protecting a witness who doesn’t obey the program’s rules. But the office, Mr. Mansfield said, will always welcome back those witnesses who behave.

Mookie, Naia, and Quanna entered the Brooklyn program in June 2002, under the worst possible circumstances: Bobby Gibson had just been slain.

The women apparently were never satisfied with the assistance. They often dropped from sight. Quanna once angrily told prosecutors: “You don’t do s– for me.”

The women caused disturbances at hotels and regularly got kicked out. They also fought with one another, complicating prosecutors’ work. On one occasion, they had to leave a hotel because two of them had gotten into an altercation with a pair of female flight attendants. Once Mookie got angry at Naia and “told everyone” where she was staying, according to one prosecutors’ memo.

Sometimes the women signed waivers declining assistance, only to change their minds. Prosecutors, meanwhile, helped the women and their families with public assistance and housing. Naia’s mother received $11,500 to set herself up in a house, but months later she was evicted for not paying rent.

A report notes that Naia is “belligerent” and does “what she wants to do,” including breaking the rules and calling people in jail. According to court testimony, she once threatened the tires on someone’s car at an undisclosed place where she was staying.

When Mookie was in danger of losing public assistance, prosecutors intervened. At one point, she was relocated out-of-state, but she soon came back – without telling prosecutors.

Mookie now faces felony assault charges. If she goes to jail, she could wind up in a special protective unit.

Harris is set for sentencing in December. Based on his criminal record, prosecutors are seeking a life sentence.

Harris’s lawyer said the women never reported being threatened when they testified against him. But now, with his sentencing approaching, at least two of the three say they are afraid.

According to a probation report obtained by the Sun, Quanna reported that she feels “her life is in danger on a daily basis.” Naia agreed, saying that since the shooting, she has been “stressed out,” drinking excessively, crying, and “hearing voices.” Mookie, the Oct. 22 report noted, was not interviewed: The probation officer wasn’t immediately able to reach her.