Lamiek Kareem Fortson may or may not have murdered Gerald Whitfield.

Twelve citizens on a D.C. Superior Court jury were supposed to decide that question. But Fortson wasn't inclined to leave his fate in their hands, prosecutors said. When he spotted a familiar face among the jurors at his trial last spring, he realized he might not have to, according to prosecutors.

Juror No. 4 turned out to be an old acquaintance named Jovanda Blackson, prosecutors said. On the day that the jury was selected, she and Fortson, 27, exchanged a knowing glance in court, prosecutors said. Later, in the ladies' room at the courthouse, Blackson ran into Fortson's wife, Erica Williams, 27, prosecutors said.

Now Blackson, Fortson and Williams have been charged with obstruction of justice, accused last week trying to rig the jury.

Jury tampering allegations are weighty accusations, and such prosecutions are rare. One reason is that the crime is not always easy to spot or prove. Cases might have to rely on inferences: What was meant by the look across the courtroom? What was said in the ladies' room? Perhaps only Blackson, Fortson and Williams can say.

Whatever the reason, Fortson and Williams apparently believed that Blackson wouldn't let them down when the jury began weighing whether Fortson helped stomp Whitfield to death three years ago in Northeast Washington.

She didn't, according to prosecutors, who say that once the jury got the case, following a week-long trial, Blackson refused to even deliberate. She made it clear she would never vote to convict, prosecutors said.

After four days of deliberations, the judge found that the jurors were deadlocked on the case against Fortson and a co-defendant, Harry Ellis, and declared a mistrial.

Judge Erik P. Christian presided over the murder trial and will preside over the retrial. On Friday, he heard evidence at a hearing on the obstruction case and ordered that Blackson, Fortson and Williams remain jailed without bond.

The D.C. Department of Corrections routinely records inmates' phone calls, and elements of the alleged tampering plot were captured on recordings of Fortson's jailhouse calls to his wife. In one call, played in court Friday, the couple discreetly discussed a person that prosecutors say is Blackson. An address book containing Blackson's telephone number and a sheet of paper with the same number turned up at the couple's Silver Spring apartment, providing another link, prosecutors said.

Whether Blackson, 27, of Suitland, was a willing participant, as prosecutors allege, or was a victim of juror intimidation, as her attorney suggested, is perhaps the biggest question to be answered as the case unfolds.

Why Blackson, who has three children and works at George Washington University, would risk her freedom to help a man she apparently knows only casually was something even prosecutors could not explain Friday.

The murder retrial was supposed to have begun last week, but after prosecutors unsealed the obstruction of justice charges, it was postponed until December.

The new accusations could affect the murder case, especially if the prosecutors, Assistant U.S. Attorneys Jennifer M. Anderson and Ann M. Carroll, succeed in joining the obstruction and murder charges. A jury then would find out that not only was Fortson charged with murder, but also that authorities believe he tried to fix his first trial.

Attorneys for Fortson and Ellis are expected to try to keep the murder and obstruction cases separate. But at least one of the current attorneys might not be able to fight that fight. Prosecutors filed a motion seeking to have Fortson's attorney, Douglas Evans, removed from the case because he is a potential witness.

Lots of legal wrangling probably will mark the next few months of the case, which began with a brutal killing June 28, 2002.

Just before 3 that morning, police officers found Whitfield, 27, covered with blood and beaten on the head in an alley in the 1600 block of Holbrook Street NE. Ellis was arrested in March 2003; Fortson was arrested months later.

Their murder trial began in May. Prospective jurors are required to inform the judge if they know a defendant or any of the attorneys. If so, the person usually is dismissed because of the potential for bias. But Blackson ignored the rule, prosecutors said, and joined the jury even though she knew Fortson.

It was divine intervention, Williams and Fortson told each other, according to prosecutors. "God had her there for a reason," she told Fortson in a phone conversation recorded by the jail.

The tapes were reviewed after the trial, when another juror contacted authorities with concerns about Blackson's conduct on the panel. From the start, the juror said, Blackson would not deliberate and insisted that she would vote to acquit.

At one point during deliberations, Blackson said she thought she knew Fortson, and the juror who later came forward asked Blackson if she had informed the judge, according to prosecutors.

Blackson did not answer, the juror told investigators.

On May 11, a day into deliberations, the jurors reported being deadlocked. Christian told them to keep trying.

On that day, according to prosecutors, Williams told Fortson that their contact on the jury needed more arguments to make to the other jurors. Fortson called back a few minutes later with suggestions, prosecutors said.

"They weren't just after a mistrial," Anderson said in court. "They were after an acquittal, which fortunately they did not get."

On May 12, notes to the judge suggested swelling acrimony in the jury room.

"What if people refuse to deliberate?" one juror asked.

"We are arguing personally. Can we leave today?" another juror asked.

On May 16, with the jury once again reporting a deadlock, the judge declared a mistrial.

Jurors' notes from the case do not identify who refused to deliberate or who took part in arguments, and Blackson's attorney said she was not the only holdout.

D.C. police detective Michael C. Irving testified Friday that the juror who came forward said Blackson unsettled the other jurors, yelling at everyone, flailing her arms and refusing to participate.

During the lengthy hearing Friday, attorneys for the three defendants challenged the authorities' conclusions, pointing out unanswered questions and, in one case, posing an alternative theory.

Blackson's attorney, Nikki Lotze, said that her client could have been recognized by Fortson and been intimidated by him and his wife into scuttling the case. In particular, she pointed to the recording played in court.

On the recording, Williams speaks of having contacted the person prosecutors believe to be Blackson and of planning to contact her again. But nowhere, Lotze said, does the recording indicate any initiative on Blackson's part.

Christian was not persuaded by the defense arguments.

Looking at the government's case in its "totality," he said, he found an "abundance of evidence" to have the case move forward.

Staff writer Del Quentin Wilber and staff researchers Alice Crites and Bobbye Pratt contributed to this report.