The 10 defendants in the Catherine Fuller murder case came to court neatly dressed yesterday, some looking like Sunday school boys in freshly pressed suit coats, shirts and ties while others projected a collegiate image in simple sweaters and slacks. Their hair had been closely cropped, Marine-style, some with stocking cap waves and sharp parts on the side.

Looking youthful and thoughtfully concerned, they could have been contestants on the television show "It's Academic," and if all that mattered was the way they looked, they could have walked away with freedom as their prize.

There was Russell Overton, 26, wearing a religious cross around his neck and pure white handkerchief in his pin-striped lapel pocket. He carried a light blue Bible and might have been taken for an oversized choir boy.

Seated on one side of him was Levy Rouse, 20, who studied the proceedings with the enthusiasm of a law school student, constantly conferring with lawyers as if he were one of them.

Alphonso Harris, 23, was the smallest of the bunch and looked like an orphan in new clothes that were a size too large. He smiled charmingly at jurors and stared childlike at his lap.

These three, along with Felicia (Luncheon Lisa) Ruffin, 17, and Charles (Fella) Turner, 21, made up the first of two rows of defendants facing the jury. Together with five more defendants in the back row, they all looked ready to begin singing from hymnals.

But there is nothing like a criminal trial to crack an image, and before this day was over all of the defendants were squirming in their seats.

It wasn't just that some of the 10 defense lawyers were indicating confusion by objecting to each other's motions. There were witnesses -- and it was the testimony of Melvin Montgomery, 22, that gave jurors the first glimpse into the life style of the gang of youths who hung out on the corner at Eighth and H Streets NE, near the scene of the slaying.

Referring to some of the defendants as "friends," Montgomery told of smoking marijuana that night and seeing the accused congregating in a park singing Chuck Brown's popular song, "Moola Y'all."

With his head cocked to one side and back turned away from the defense tables, he repeated the lyrics he had heard that night.

" 'We need some money,' " he said. " 'We gotta have money.' "

Now the defendants were on the edge of their seats.

Rouse, who had until then maintained a scholarly manner, was staring with squinted eyes at Montgomery.

Montgomery, who was clearly perturbed, eased back from the microphone only to be admonished by D.C. Superior Court Judge Robert M. Scott to "sit up and speak up."

With a manner that suggested illiteracy, Montgomery continued, "Den somebody say dey gon git dat one. Bobo wa pointin' in dat direction. She wa on da corner."

Overton, with Bible in hand, was the man called "Bobo." Prosecutors have alleged that it was he who grabbed Fuller from behind and dragged her along a glass-strewn alley into a garage.

The studious-looking Rouse allegedly had shoved a foot-long pipe into Fuller's rectum as she was being beaten to death.

It was the smiling little Harris, nicknamed "Monk," who prosecutors charge jumped around shouting, "Do it again," as the pipe was shoved in the first time.

The other defendants, who are alleged to have participated in kicking and hitting Fuller, who died Oct. 1, 1984, are Timothy (Snot Rag) Catlett, 20, Kelvin (Hollywood) Smith, 20, Christopher D. (Chrissie) Turner, 19, Steven Webb, 20, and Clifton Yarborough, 17.

The nicknames were repeated over and over in court testimony yesterday. And by the time recess was declared, it was clear that whatever image the defendants were trying to project, there was more to them than met the eye.