A Rockville man was sentenced yesterday to life plus 50 years in prison for crimes he committed after bureaucratic bungling enabled him to walk away from the Montgomery County Courthouse instead of being turned over to District of Columbia officials to serve time in prison.

Montgomery County Circuit Court Judge William Cave sentenced Robert Armstrong White, 26, to life in prison for the rape last May of a Silver Spring woman, 20 years for robbing her, 20 years for burglary and one year for carrying a concealed weapon.

Cave also sentenced White to 10 years for an arson conviction in an unrelated case. "We can't take the risk that Mr. White will ever again threaten society," Cave said, ordering that all but the one-year weapon sentence be served consecutively.

White was paroled Feb. 6, 1984, from the Maryland Correctional Training Center in Hagerstown after serving three years of a five-year sentence for battery, theft and weapons convictions. On that day he was turned over to Montgomery County sheriff's deputies to be taken to the county court to answer a contempt charge in a paternity suit filed by his former girlfriend, Lisa Perkins, 22.

Before he left the Hagerstown prison, D.C. officials had filed papers to ensure White would be transferred to Lorton Reformatory at the end of his Maryland prison term. He was scheduled to begin serving a 13-to-40-year sentence for armed robbery, armed rape, armed kidnaping and weapons convictions.

Instead of being handed over to District authorities, however, White was released on personal bond after a brief hearing on the contempt charge before Circuit Court Judge Irma Raker. Raker did not know White was wanted by the District because the D.C. papers had not been sent to Montgomery County with him.

Less than two weeks later, prosecutors said, White set fire to Perkins' Bethesda apartment. Three months after his mistaken release, according to prosecutors, he broke into the Silver Spring home of a woman and raped and robbed her at knifepoint. It was those crimes for which he was sentenced yesterday.

In a telephone interview yesterday, Wayne Winebrenner, warden of the Maryland Correction Institution in Hagerstown, said that a prison officer forgot to give Montgomery sheriff's deputies White's papers when he was released to their custody on Feb. 6, 1984. When correction records supervisor Ava I. Gift noticed the mistake and called the sheriff's office to ask the deputies to return for the papers, she was told to mail them because the return trip would entail overtime, according to Winebrenner.

But in an interview in his office, Sheriff James Young said those papers did not arrive at his office until three weeks after White walked out of the courthouse.

"It's true that they didn't actually have in their hands a copy of that paperwork," Winebrenner said. "On the other side, the deputies should not have received [White] without having that paperwork."

Chief Deputy Sheriff Raymond Kight countered, "I think they made a mistake and they're trying to blame us -- 'Oh yeah, we made a mistake and didn't send the papers but it's still the sheriff's department's fault.' "