Both sides agreed that Willie Smith, a guard at the new D.C. jail, suffered a broken jaw last June 17 in a fight with David Preston Calaway, an inmate.

In fact, Smith's jaw was broken in three places and he spent 3 1/2 weeks in Providence Hospital while it mended.

Moreover, there was no dispute over the fact the Calaway, 36, had struck Smith with a metal tray he took from a steam table from whic prisoners were served meals.

There was no dispute that Smith was the only guard actually in the unit of the new jail known as Northeast. Two and that about 40 prisoners watched the two men struggle until another guard arrived and broke it up.

There was no evidence that Calaway was injured or even that Smith had struck him.

The only question for the jury in D.C. Superior Court was who had started the fight.

The answer to that question would decide whether Calaway was guilty of assault with a dangerous weapon, to wit, the metal tray as the government charged, or whether he had merely been defending himself from Smith.

"This is a classic confrontation between the captured and the people who administer to them," said John Sansing, Calaway's court-appointed defense attorney.

"Inmates have rights," said Assistant U.S. Attorney Mark H. Tuohey III, the prosecutor. "But let's consider the rights of correctional officers."

Officer Smith testified that he had been serving cake at the evening meal in Northeast Two; that, Calaway had asked for a second piece, that he had refused on the ground that there was only enough for each prisoner to have one serving and that Calaway had struck him moments later.

Thomas Robinson and Clifford Bailey, two inmates, testified that Smith had refused to give Calaway even one piece of cake. They said he made insulting remarks of Calaway, threatened him with a knife, and pushed him.

Two other officers testified that guards must pass through metal detectors as they enter the jail and that they are forbidden to carry knives or any other weapons while among the inmates.

Smith told the jury that he had "not even owned a knife since I was a boy."

After deliberating about 90 minutes, the jury of 11 women and one acquitted Calaway yesterday. He showed no emotion.

He is to be returned to the federal penitentiary in Atlanta, where his is serving a 10-to-30 year sentence for burglary.

The burglary conviction arose from a case in which he also was charged with murder and assualt in the slaying of Adele Nicole Solomon, a 21-year old George Washington University student. Her body was found in her apartment at 1415 Hopkins P1. NW last March 23. She had been strangled.

A note purportedly written by Calaway, as well as one of his fingerprints, was found in the apartment. The jury in that case found Calaway guilty of burglary after finding him innocent of murder and assault.