A 19-year-old Northwest Washington woman was charged yesterday with threatening to kill three of the 12 jurors who returned a guilty verdict Tuesday in the armed robbery trial of a friend.

After the jury announced its verdict and was excused, two women and a man who served on the panel were confronted at the main entrance of the D.C. Superior Court by the woman, who was carrying an infant, and a 16-year-old juvenile. The two shouted expletives and made a death threat to the jurors, according to witnesses.

Betty Williams, who headed the jury and was one of the three persons, said yesterday that she was "shocked and very frightened by the threats. "This was my first time on jury duty and I think this will be the last time I'ii ever serve."

Williams said her nerves had been so shaken by the incident that she did not return to work yesterday.

"I guess the threat was more or less directed at me because I was the foreperson," Williams said. "I didn't mind being on a jury and doing my civic duty. But I had no idea that my life would be threatened."

Immediately after the incident, Williams and the two others rushed into the courthouse -- with one of the women in tears -- and back to the courtroom where the trial was held. There they met Assistant U.S. Attorney Jerry D. Bernstein, who served as prosecutor during the trial.

Bernstein escorted the jurors to a nearby room where they were guarded by deputy U.S. marshals until police arrived to question them.

Police arrested Shelia Brown of 5613 14th St. NW, who was charged with obstruction of justice and felony threat. The 16-year-old was also charged with threatening the jurors.

Brown had served as a defense witness in the trial of her friend, Belinda Hagins, who was charged with armed robbery and attempt to commit robbery while armed.

Superior Court Judge W. Byron Sorrell released Brown on her personal promise to return to court in the case.