The hand-drawn poster on the wall at Bethesda-Chevy Chase High School gave only a hint of the emotions at the school this week. "Keep Lauriat," it said. "Sign petitions. Write Superintendent Bernardo."

The talk was more direct in the knot of students outside the old, red-brick structure. "We want Dr. Lauriat back. Everyone is up in arms about it," said Betsy Karmin, a junior. "We want him back because he's a good man and he does a good job."

Her comments and the poster reflect a bizarre turn of events that has made the B-CC principal, F. Thornton Lauriat, the focus of a rare student-faculty protest movement in a period of campus calm over one of the most unlikely issues imaginable.

It all started last Thursday when Lauriat was put on administrative leave after he pleaded no contest to a charge of shoplifting a cassette tape and a box of staples worth $8.58 from a Giant Department Store.

Within hours, the school faculty and the executive board of the school Parent-Teacher-Student Association (PTSA) were meeting in emergency session. Both promptly fired off letters and telegrams of protests.

The next day, two student groups collected 1,100 signatures on petitions and presented them to Montgomery County school officials. "We consider F. Thornton Lauriat a responsible and honorable man.His tenure at B-CC has been very effective," one petition said. "We realize he's made a mistake in judgment but we do not feel this will change the excellence of his duties as principal."

"Apathy has been a real problem here and across the country. It's grabbed us all, and it's something very hard to shake," said Mark Quarterman, editor of the student newspaper, the Tattler. "But there hasn't been any apathy around here the last few days. Students are excited. They're concerned. We collected 1,100 signatures on our petitions Friday and we could have collected more if we had time."

Meanwhile, Lauriat, who was sentenced to six months unsupervised probation for the shoplifting incident, remains in an official limbo with the school system. He has been temporarily removed from his post, but continues to receive his $31,635 annual salary, Montgomery County school spokesman Kenneth Muir said yesterday Lauriat's situation is under investigation and a decision on his permanent status is expected within a week.

The incident threw Quarterman, a senior, into the center of the controversy. He drew up one of the petitions and for a time the student newspaper staff was divided over whether or not to publish a story on the principal.

"Intially, the editors decided collectively that nothing would be printed," said faculty adviser John Barrett. "There were two reasons. First, it wasn't news. Everyone at the school knew about it. Secondly, they wanted to protect the principal."

After agonizing over the issue two days, Quarterman decided that the paper would report the incident and the petition drive. He also wrote an editorial urging that the principal be retained. "My feeling is he's been punished,' the student said yesterday. "He's paid his dues to society, and he should be allowed to come back to school."

Shoplifting is different from corruption. Dr. Lauriat didn't use his office for financial gain," he continued. "Spiro Agnew (who pleaded no contest to tax evasion charges before he resigned) abused his office. Dr. Lauriat didn't abuse his office."

But while most students and faculty members in the 1,500-student school support Lauriat, doubts linger among some. "It really contradicts every impression I've ever had about the guy, said Tom Stokes, a senior, who signed one of the petitions."I don't see how he can preserve discipline after this. You could strike down anything he told you. He was a good principal, an idol you could look up to. Now I don't know what to think."

The most perplexing part of the case is why a well paid, respected school principal would jeopardize his career by shoplifting a tape cassette and box of staples worth only $8.58.

Lauriat, 39 offered no explanation when he entered his plea, or when interviewed yesterday. He said his attorney and school officials advised him not to discuss the issue.

But theories abound at the school. Some speculate that he became frustrated waiting in the line at the store checkout counter and stormed out with the items. Others attributed it to "temporary insanity" or "some kind of sickness." But most interviewed speculated that maybe the pressures of the job just got to him.

"He always made it a point to be at every student activity, every play, every athletic event, every meeting. I think he maybe outdid himself," said Dr. Lee Boyette, a guidance counselor. "It could be the pressures just built up to him."

"I've been in this business 15 years and he's one of the best (educators) I've dealt with," he added.

Lauriat, as Boyette and others describe him, is known for his open-door policy, his informal manner with students and his concern over the personal problems of teachers and students.

"He's kind of a good neighbor and good Samaritan," said Nancy Gallagher, a B-CC teacher. "There's a real sense of sincerity about him. More than anything, it's his sense of compassion that sets him apart from others. We're all very disturbed by all this."