Three teachers from Suitland High School told a military jury today that they remembered Mitchell T. Garraway Jr., a sailor facing a possible death sentence, as a polite and peaceful young man.

The teachers, whose acquaintance with Garraway dates from the time he lived in Suitland and attended their classes, said he shunned alcohol and drugs at a school plagued by fights and a serious drug problem.

They testified as a presentencing hearing resumed in Petty Officer Garraway's court-martial. He was convicted Jan. 30 of premeditated murder in the fatal stabbing of a lieutenant aboard the frigate USS Miller June 16 off Bermuda.

Testimony is scheduled to resume Thursday morning, and the court-martial panel, composed of four officers and four enlisted men, is expected to begin deliberating Friday. Garraway, 21, faces life in prison or the death penalty. A unanimous vote by the panel is necessary for execution. Garraway would be the first person the Navy has put to death since 1849.

Judith A. Stephan, a Suitland English teacher, said she often "nagged" Garraway when she had him in class his junior year because, like many of his schoolmates, he did not work up to his potential.

Another English teacher, Linda Colomo, said Garraway flunked her class when he repeated it his senior year. But he seemed not to hold a grudge against her for failing him, she said.

Science teacher Vincent S. Curl said Garraway "was a kid you'd never think would be involved in an incident like this."

But Curl, who had testified he was a Secret Service agent in Washington before becoming a teacher in the early 1970s, said he "had a gut feeling something was bothering the kid."

In light of that feeling, Curl was asked under cross-examination by the prosecutor whether as a Secret Service agent he would have permitted Garraway near the president.

"In retrospect, you couldn't let him near him . . . . You couldn't afford to," said Curl.

Garraway, who is black, was convicted of killing Lt. James K. Sterner, 35, of Woodbridge, N.J., who was white, in a passageway of the frigate. During the trial, Garraway's defense lawyers said he was extremely sensitive to racism aboard the Miller partly because he had grown up in a majority black environment and was not prepared for prejudice he encountered in the Navy.

Sterner was responsible for temporarily holding up Garraway's promotion to Petty Officer 3rd Class, his present rank, according to testimony.