Eight seniors at the exclusive Landon School in Bethesda, including some members of its top-ranked lacrosse team, have admitted to cheating on the SAT, a test widely used by colleges to help determine who will get in.

School administrators began an investigation two weeks ago after noticing some suspiciously high SAT scores.

"We began to see greater improvement than we would have predicted. That doesn't mean anything by itself. But we began to see that there was something of a pattern," said Damon F. Bradley, headmaster of the all-boys school, which includes grades 3 through 12 and charges tuition of about $20,000 annually. "Right now, we're dealing with probably eight students. We're also in the process of talking with others."

Bradley said the eight students admitted to cheating on the SAT exam that was administered Oct. 12 at the Holton-Arms School, an all-girls private school in Bethesda. There were more than eight Landon students in the room, he said, as well as students from other area schools.

"Our investigation is continuing," Bradley said. "We don't want to land on a number, think the matter is resolved and find we either misjudged someone who hadn't done it or missed someone who had."

Punishment, he said, is being determined by the student honor council and by school officials, with an announcement expected by early next week. "There will be punishment," Bradley said. "Severe punishment."

Landon's student handbook calls for three- to five-day suspensions for first infractions at the high school level. Expulsions are rare and have been limited to serious, repeat offenders, school officials said. The student honor code calls for infractions to be noted but no suspensions given if students admit to the cheating.

"Even though we wish they never had gotten themselves into this predicament," Bradley said, "we think it is fundamental that they came forward."

He said rumors had been rumbling through the school before the eight boys showed up, some with their parents, outside his office last Saturday to confess.

Rob Bordley, the lacrosse coach and a history teacher at the school for 33 years, said he knows the boys who admitted to cheating. Bordley said he was "immensely disappointed" and believes they succumbed to peer pressure.

On the day of the SAT, the room at Holton-Arms was at times loosely monitored, sources said. According to Bordley, "some chitchatting started, and the next thing, kids were exchanging information. These were good kids who made some bad decisions."

Why those decisions were made is mystifying to him, he said. Landon is a school whose average SAT score runs about 1335 out of a perfect 1600. "In a couple of cases, the kids were already preapproved to be admitted to schools," Bordley said. "They didn't need higher scores."

Tom Ewing, spokesman for the Educational Testing Service, which administers the SAT, said cheating is not uncommon. Of about 2 million tests taken each year, 2,000 will be reviewed by ETS for irregularities. Its computer automatically looks for combined math and verbal scores that have risen by 350 points from one test administration to the next.

Out of the tests reviewed, Ewing said, about 500 will be thrown out and the scores canceled because of cheating.

"Copying is the most common form of cheating," Ewing said. "In rare cases, one student might impersonate another. We catch all of those."