A 25-year-old Northwest Washington man who confronted three prosecution witnesses on the morning of his bank robbery trial and tried to convince them not to testify against him was sentenced yesterday to serve the maximum term of five years in prison for obstruction of justice.

U.S. District Court Judge Louis F. Oberdorfer told the defendant, Avery Barber, that he wanted "the word" to go out from the courthouse "that anybody who messes around with witnesses in a federal court is playing with maximum time."

Barber, who was accused of recruiting bank robbers from public housing projects, abruptly pleaded guilty to the bank robbery charges last January after the witnesses went to the U.S. Attorney's office and revealed that Barber had approached them in the courthouse corridors and in an elevator.

Assistant U.S. Attorney Deborah A. Robinson told Oberdorfer that the government's evidence would show that when Barber approached the witnesses in the courthouse, he told them not to "snitch" on him and offered them money -- the same as they wouild get for testifying -- if they would go home. Robinson also told Oberdorfer that Barber told one juvenile witness that if he testified "he wouldn't be able to walk the street much longer."

Barber pleaded guilty to the obstruction of justice charge. During a brief sentencing hearing, Oberdorfer told Barber that "this whole society will unravel" if witnesses could not feel free to come into the courthouse to testify and "tell the truth."

Another federal judge had sentenced Barber to serve three to nine years in jail on the bank robbery charges.Oberdorfer ordered that the five-year term for obstruction of justice run consecutively to the sentence in the bank robbery case and to another 20-months-to-five-year sentence that Barber must serve for a probation violation in an unrelated case. The combined sentences mean Barber will have to serve a minimum term of nine years and eight months in prison