Jolanta Little was determined not to change his mind.

Little, 22, was a key witness in the upcoming murder trial of a Washington woman shot dead in 2008 before she was scheduled to testify against an accused local drug dealer.

But last week, just days before the murder trial was supposed to begin, Little told prosecutors he would not cooperate. “I’ll give you some time to think about this,” D.C. Superior Court Judge Robert E. Morin said. Little bowed his head — then looked up and responded: “I’ve thought about it. No.”

Little was scheduled to testify in the murder trial of Willie Walker Jr. and Ricky I. Donaldson. Prosecutors said Walker ordered Donaldson via jailhouse letters to kill Delois Persha, 44, because she planned to testify against Walker in an upcoming trial.

Now, those prosecutors have asked to delay the trial for two or three months — to regroup after losing Little.

“We have an obligation as members of the community to make sure we have the best case,” Assistant U.S. Attorney Alessio Evangelista told the judge at a hearing last week. Prosecutors said they also planned to investigate whether Walker or Donaldson, in the D.C. jail, somehow influenced Little’s decision.

Persha’s death highlights the danger sometimes facing witnesses who come forward to help prosecutors, especially in cases involving violent crimes. And Little’s refusal to testify punctuates the point. When physical evidence is lacking, prosecutors and police rely heavily on eyewitness testimony to secure convictions. But sometimes, those witnesses are targeted. Other times, they aren’t willing to take the risk.

“People realize if someone kills, they’ll kill again, and the next time it could be a member of their family,” said Ronald Moten, co-founder of the D.C. outreach group Peaceoholics. Moten urges D.C. residents to cooperate with police when they see a crime, but he recognizes that testifying can be frightening.

“There is a fear of retaliation,” he said.

Prosecutors say witness intimidation is rare in the District, with hundreds of area residents testifying in trials each week without threat of violence. The U.S. attorney’s office in the District offers a variety of security services through its Emergency Witness Assistance Program, including moving victims or witnesses to improve their safety.

In 2012, the program assisted 168 witnesses and 308 family members with either transportation or relocation services, according to Bill Miller, a spokesman for the office.

But some witnesses reject authorities’ efforts to keep them safe. Sometimes they flatly reject relocation assistance; other times they venture back to the neighborhoods where they lived — against the advice of prosecutors.

In 2009, Crystal Washington, 44, was shot dead in broad daylight as she stood at a Northeast Washington bus stop. Prosecutors said a District man ordered an associate to kill Washington because she was scheduled to testify against him in a trial set to start two days later. Washington was not receiving protection from the U.S. attorney’s office, but she had been staying at a halfway house, which she had left and planned to return to on the day she died.

Mark Pray, 33, and Alonzo Marlow, 32, were convicted and sentenced to life in prison. “The murder of a government witness is the ultimate obstruction of justice,” the government’s sentencing memorandum said.

Last year, Anthony Waters, 44, was sentenced to life in prison for the 2010 fatal shooting of Derrick Harris, 37, in Southeast Washington. Authorities said Harris, who had declined advice from the prosecutor’s office to stay away from his old neighborhood, was killed because he had testified against one of Waters’s friends in an earlier drug trial.

And in December, authorities in Prince George’s County said Nicoh Mayhew was fatally shot standing outside his Seat Pleasant apartment after declining to receive protective services from the county.

“We can’t force someone to take it,” said John Erzen, a spokesman for the Prince George’s County State’s Attorney’s Office. Mayhew, who was holding his 2-year-old son when he died, was scheduled to testify against his uncle in an upcoming murder trial. The boy was also hit but survived.

Erzen said witness intimidation remains unusual in Prince George’s. Out of the thousands of cases prosecutors have handled since 2011, for instance, they logged only six instances of witness intimidation — and rarely felt the need to offer relocation packages, he said. Last year, the office relocated eight individuals cooperating with authorities; the previous year, the number was 11.

In the District, the numbers are less clear. Miller said the U.S. attorney’s office does not keep track of that data. Miller said Persha, the mother of a young girl, was receiving help through the office’s Emergency Witness Assistance Program.

According to Persha’s sister, she was moved to another neighborhood and lived in a government-paid hotel room for about a month. But then she returned to the LeDroit Park neighborhood where she grew up, the sister, Debra Persha, said.

“She never thought anything would happen to her,” Debra Persha said.

Walker was in jail at the time of Delois Persha’s death, and according to prosecutors, he wrote to Donaldson to order her death. Prosecutors said the two men used sexual references in letters that were a code for shooting her.

On Sept. 13, Persha was sitting on a ledge smoking a cigarette near a school in the 300 block of V Street NW. According to the 80-count indictment, Donaldson, wearing a ski mask and carrying a .38-caliber revolver, tried to shoot her in the head — but the gun didn’t fire. Persha pleaded with Donaldson not to kill her, then jumped from the ledge and ran, according to the indictment. Donaldson pointed his gun again and fired, knocking her to the ground. As she tried to get up, Donaldson stood over her and shot her three more times, the indictment said.

Both men, through their attorneys, argued they had nothing to do with Persha’s killing.

The two men were initially facing at least 100 years in prison on charges of first-degree murder. But prosecutors offered plea deals reducing the charge to ­second-degree murder and agreed to recommend a sentence of 25 to 32 years.

That plea deal has angered Persha’s family. But the defendants refused to take it, according to their attorneys, Gladys Weatherspoon and Archie Nichols.

Now, with Little’s refusal to testify, it’s unclear when the trial will proceed. Weatherspoon said in court last week that, after more than four years, her client is ready to go to trial.

Little, meanwhile, sits in D.C. jail, where the judge sent him after ruling him in civil contempt for refusing to testify. Little has been in jail since he was convicted in a 2008 carjacking and sentenced to 11 years behind bars. The judge reminded Little that while he was in jail for refusing to testify, he would not earn time toward his carjacking conviction. Little, as he was escorted out, said he understood.

Magda Jean Louis contributed to this report.