A D.C. Superior Court judge ruled yesterday that he would not seq uester the jury in the trial of 12 defendants in the slaying of Catherine L. Fuller, rejecting defense motions that it would be difficult otherwise to ensure a fair trial.

Judge Robert M. Scott, acting on the fourth day of pretrial motions, said he decided to reject the defense requests because housing jurors away from their homes at night would make jury selection "much more difficult," eliminating a "great number of people" who had to take care of their children or had other obligations.

Several of the lawyers for the defendants charged in the beating death of Fuller last October had argued that their clients might not receive a fair trial if jurors were allowed to go home at night to their families and neighborhoods where they might hear comments about the case or see news reports.

The lawyers pointed to the extensive publicity surrounding Fuller's death in a Northeast alley and garage and to the coverage of pretrial motions during the last week. Police allege that Fuller, 49, was severely beaten and kicked by a number of the defendants as they attempted to rob her. A medical examiner ruled she died of blunt force injuries to her entire body.