A man convicted of what the Fairfax County prosecutor terms "absolutely one of the most brutal murders I've ever tried" has spent the first three years of his 15-year sentence, which normally should be served in Virginia state prisons, as a cook at the Fairfax County jail.

David J. Voetsh, 21, who was convicted in 1975 of the stabbing murder of a West Springfield woman and the felonious assault of her husband, has become a "main trusty in the jail's kitchen according to Fairfax County Sheriff's Department sources. He has made frequent trips outside the jail to Richmond with a deputy sheriff to buy a supplies for the jail, the sources said.

Commonwealth's Attorney Robert F Horan, who prosecuted Voetsch, said yesterday there were no financial improprieties in the county's keeping Voetsch because the state pays for the cost of imprisoning all state prisoners.

Horan also said that it is legally permissible for Voetsch to travel around the state as long as he is in the custody of a deputy sheriff.

Three years ago Fairfax County Sheriff James D. Swinson a better to the Virginia Department of Corrections, asking that Voetsch be kept at the jail because he was needed as a cook.

"This boy comes from a fine family," Swinson said about Voetsch in a recent interview. He said that Vietsch was given a 5-hour pass last winted to go out with his parents for dinner because of "humane reasons."

Swinson said that just because a man is charged with murder doesn't mean he is all that vicious."

A spokeman for the state's Department of Corrections said yesterday it is "unusual but not rare" that a sheriff will request to keep a convicted felon at his jail."

The way things have been in the past few years with the overabundance of convicted felons in county jails, normally the sheriffs are on your backs to take them (the felons) off our hands," said Wayne J. Farrer, a Department of Corrections spokesman. "When a sheriff asks to keep a felon, we are happy tp accommodate him," Farrer said.

Swinson has been a persistent critic in the past of the state's refusal to accept convicted felons from local authorities plagued with overcrowded jail facilities.

"The localities are bearing the brunt of this. We're taking the rap," Swinson said in an interview two years ago. "The state says they don't have the beds. Where the hell they think we're going to get them?"

Court papers on Voetsch say that he is tobe confined in the penitentiary for 15 years." In Virginia however, according to Farrer, it has been a practice to permit a sheriff to request that a felon stay in his jail if the inmate can offer a needed service.

The practice, according to Farrer, usually requires the approval of the sentencing judge. Circuit Court Judge Barnard F. Jennings, who sentenced Voetsch, said yesterday he did not know that Voetsch was being kept in the jail until he saw a list of inmates.

The judge said he spoke to Swinson about Voetsch and was satisied with the sheriff's explanation that he needed an assistant cook to help out at the jail.

The Fairfax County jail, like many jails across the state is currently overcrowed, according to Chief Sheriff's Deputy M. Wayne Huggins. Huggins said that 10 inmates from the jail are now "farmed out" to other institutions.

There are about 830 convicted felons in county jails awaiting space in state penitentiaries, according to the Virginia Department of Corrections. This number is down from past years, when more than 2,000 felons were held in the jails, because of expansion in the state prison system, a Department of Corrections spokesman said.

Voetsch, according to Huggins, is the only convicted felon in the county jail.

Voetsch pleaded guilty in December 1975 to the second-degree murder of Rebecca Barber, 29, and the felonious assault on her husband Joseph C. Barber Jr., who suffered a fractured eye socket and permanent eye damage trying to defend his wife.

Horan said the Jan. 26, 1975, murder occurred after a party at Barber's house when the woman refused the sexual advances of Voetsch.

The practice of inmates' traveling with sheriff's deputies, Horan said, has led to conjugal visits for inmates and, in one instance in 1975, led to a trip by a inmate and a deputy for a day at the Charles Town, W. Va, racetracK.*

The country sheriff's department has been under investigation for alleged misuse of inmates by sheriff's deputies for nearly four months. Horan, who is conducting the investigation, says he has found "a great many" misdemeanors that occurred more than a year ago and thus cannot be prosecuted under Virginia law.