Twelve defendants charged in the beating death of Catherine L. Fuller last October in a Northeast Washington alley rejected a last-minute government offer yesterday to reduce their murder charges in exchange for guilty pleas.

Also yesterday, as a D.C. Superior Court judge heard pretrial motions in the case, Assistant U.S. Attorney Jerry S. Goren revealed that one person arrested in the case, Harry Bennett, had agreed to plead guilty to lesser charges of manslaughter and robbery in exchange for testifying against the other defendants.

All 12 defendants, many in their late teens, have been charged with first-degree murder, kidnaping and robbery in Fuller's death, and if convicted must be sentenced to a mandatory term at least 20 years in prison before becoming eligible for parole.

According to sources, the U.S. attorney's office yesterday offered to reduce those charges to a single count of second-degree murder for the majority of the defendants if all agreed to plead guilty.

One defendant, alleged to have led the attack, was told he could plead guilty to second-degree murder and robbery, while at least one other defendant, alleged to have played a minor role, was offered even lesser charges than second-degree murder, sources said.

Second-degree murder carries a maximum prison sentence of 15 years to life and does not require a mandatory prison term.

The 12 lawyers and their clients, however, decided to reject that offer yesterday during a closed courtroom session described by some sources as disorganized and uneventful and by others as emotional.

During the meeting, sources said, at least one lawyer urged the others to consider entering a group guilty plea, but there was never much support for that position.

The unexpected offer by the government came during the second day of pretrial motions before Judge Robert M. Scott and only days before the expected start of the trial, which has gained wide publicity due to the number of defendants, the largest ever in a murder trial in the District, and the alleged brutality of the crime.

Fuller's battered body was found partly clad in a glass-strewn garage in an alley behind the 800 block of Ninth Street NE, near Fuller's home.

After an autopsy, the medical examiner ruled that Fuller had died of blunt force injuries to her entire body. The medical examiner said she also had severe lacerations from being dragged across glass.

According to police and transcripts of some defendants' police statements, Fuller had been seen stuffing money into her bra at a neighborhood store, followed as she walked home, and dragged into an alley. Once in the alley, police allege, the defendants began to kick and beat Fuller with their fists and sticks, ripping her clothes, as they attempted to take her jewelry and money.

Police allege she was dragged into a litter-strewn garage where the beatings continued and more of Fuller's clothing was removed, and that a pipe-like object was repeatedly rammed into Fuller's rectum while some assailants held open her legs and others cheered.