A federal jury in Washington deadlocked yesterday on whether to render death sentences against two of the most violent convicted killers in the city's history, a stalemate that will result in life prison terms with no parole for both men.

Jurors could not agree on sentences for Kevin L. Gray, whom they convicted of 19 murders, and his co-defendant, Rodney L. Moore, convicted of 10. The jury declared that it was hopelessly divided yesterday morning after more than five days of deliberations. It was the third time the panel delivered such a message to the judge, and this time, he decided to call an end to the case.

"The court will declare these proceedings to be at an end and will impose a sentence of life in prison on both defendants," U.S. District Judge Royce C. Lamberth said from the bench.

Gray, 31, showed no reaction. Moore, 37, smiled slightly.

The longest trial in the city's history was over moments later, ending more than 10 months of proceedings that delved into the killings and drug dealing of a gang that investigators dubbed Murder Inc. The outcome left many questions unanswered in only the second capital punishment case to go to trial in three decades in the District, a city viewed as a bastion of anti-death penalty sentiment.

The jury's 66-page verdict form was shredded, erasing the record of the jurors' consideration of the factors weighing for and against execution. The final vote was not revealed to anyone. The jurors -- whose names were kept secret for security reasons -- rejected a chance to talk with reporters in a courthouse setting that would have preserved their anonymity, and they left the building escorted by federal marshals.

Lamberth barred attorneys from talking about the case, as other defendants in the same indictment face trial later this year. No one in that trial faces execution.

Attorneys for Gray and Moore told Lamberth yesterday that they will request a new trial.

Death penalty opponents hailed the outcome. "It's a great victory for keeping the death penalty out of D.C.," said Michael Stark, a spokesman for the local branch of the Campaign to End the Death Penalty. The nonprofit group had mounted a petition drive to protest the government's decision to seek execution, a decision approved by Attorney General John D. Ashcroft.

In 1992, D.C. voters rejected a local death penalty measure that Congress ordered the District to put on the ballot. City leaders rallied against the forced vote as an encroachment on home rule. The prosecutions of Gray and Moore took place under federal law, which makes the death penalty an option in certain cases.

At a time when the fairness of the death penalty is being widely debated, it was notable that some members of a D.C. jury would hold out for the death penalty. In the only other recent capital case to go before a D.C. jury, in 2001, a panel decided within four hours against sentencing gang leader Tommy Edelin to death for four killings.

Before the Edelin trial, the last death penalty case in the District, in 1972, ended with a federal jury sentencing a hit man to die, but he was spared when the Supreme Court ruled that same year that U.S. death penalty statutes were unconstitutional. Congress enacted a new federal death penalty law in 1988. The last execution in the District was in 1957.

The jurors' notes to the judge during deliberations told of their struggles.

"For each count, there are jurors who favor imposition of the death penalty who believe that changing their position would require them to surrender their honest convictions," the jury's final note read. "For each count, there are jurors who favor imposition of a life sentence without possibility of release who believe that changing their position would require them to surrender their honest convictions. Accordingly, there is no prospect that this jury will reach a unanimous verdict."

The note was signed by all 12 jurors, who used their juror numbers instead of their names. It was their third note informing the judge of an impasse. One was written on Monday and the other on Wednesday. The jury had 10 black members and two whites; five jurors were women, seven were men.

In January, the jury convicted Gray and Moore of ordering or carrying out 29 murders in their 10 years of leading the drug crew. The charges that made them eligible for the death penalty were murder committed in aid of racketeering and murder committed as part of a continuing criminal enterprise. Four other defendants were convicted along with Gray and Moore, but they did not face death penalty charges.

In his order keeping the names of jurors a secret, Lamberth cited evidence that "defendants are alleged to have committed multiple murders and assaults in order to prevent witnesses from contacting the government." He said that providing a list of members of the jury pool could jeopardize their lives.

The trial was without parallel in the history of the city's criminal courts. No one else was ever charged with or convicted of as many slayings as Gray and Moore, and because of the unusual nature of the death penalty proceedings, Lamberth summoned 1 percent of the city population last spring for possible jury service. He questioned 695 people to find the final 12.

The verdict form for the initial phase of the trial, to determine whether the defendants were guilty or not guilty, contained 115 felony counts against some or all of six defendants. The verdict form for the death penalty phase contained dozens of aggravating or mitigating factors , each requiring a vote.

It is not known whether the jurors completed that form or on what points they deadlocked.