Montgomery County Police Chief Robert J. diGrazia said yesterday his officers have been conducting surprise drug raids in county schools because school officials failed to cooperate with earlier police attempts to curb student drug use.

Three more arrests yesterday - two 16-year-old girls and a 20-year-old school employe at Seneca Valley High School - brought the total to 92 arrests in raids at high schools throughout the county in the last two weeks.

Montgomery PTA leaders and parents, including parents of some of the students who have been arrested, continued to praise the police crackdown yesterday.

But county school officials complained about the police tactics and suggested that deGrazia had ordered the drug raids to improve relations with his officers, who last month publicly expressed their "frustration and dissatisfaction" with diGrazia's leadership of the department.

The school officials said they were displeased with how undercover police officers had conducted surveilance of students in the schools and that police staged the drug raids without first informing school authorities.

"In the past, it was customary to let principals know if police saw drug activity," said Ann Meyer, principal of Gaithersburg High School. "I would like to keep that connection."

But diGrazia said that when police notified school officials before staging drug raids in the schools last spring "pretty soon the information would get out that cops would be there."

He said he was not suggesting that school officials warned the students. But he said that school monitors, non-teaching employes who patrol school hallways and maintain discipline, frequently identified undercover police officers and the information leaked to the students.

The current surprise raids are being conducted, diGrazia said, "to get the word out about the kind of problem we have in the schools. Maybe now somebody will wake up to it. If I had known the program was going to work this well. I would have started it a long time ago."

Dr. Kenneth K. Muir, a spokesman for the Montgomery school board, said that school officials did not ask police to arrest students daily, as they have been. "If you have a suspicious mind," Muir said, "you might think that diGrazia was reacting to criticism by county officials or to (last month's) vote of no confidence by his men. If you're on the defensive, you take the offensive."

Carroll Ruark, an assistant principal at Seneca High School, said that when police arrested four students in a wooded area near the school several days ago, the officers refused to give the school the names of the students. "If we're really talking about helping these kids and working with them," Ruark said, "we have to know who they are."

Both the school principals and police officers say they are looking forward to the time when police can turn over the drug control program to the schools. Montgomery County Executive James P. Gleason said yesterday that he hoped to help the schools take over "as soon as possible, because we can't keep this up for too long."

But diGrazia said that "as long as we keep going to these schools day after day and keep finding kids out there, even though they know we're coming, we have to keep it up. I'm not sure how long we're going to have to do it. It looks like it could take awhile."

Police planning for the drug raids began almost a month ago when district station commanders were told at a staff meeting that they had the chief's go-ahead to set up undercover surveillance teams in the schools.

Each station commander has organized the operation in his district, deciding to which schools to send undercover officers and ordering the various raids. But the commanders have kept in touch with diGrazia by phone and have fed information about possible drug sellers to vice squad officers, who diGrazia said will try to identify major drug supply routes into the county.

One district commander, Capt. Ralph Robertson of Bethesda, said yesterday that "the response (to the raids) has been fantastic. We've gotten more calls on this than on anything else we've done in my 20-year career, and nearly all of them have been favorable."

Robertson said he had even been praised by parents of two students whom his men arrested at Walt Whitman High School yesterday. "They agreed that this is a problem that needs to be controlled," Robertson said.

Georgia Smith, president of the Walt Whitman PTA, said she would not mind if police kept the schools under constant surveillance. "Those who aren't doing anything wrong won't be bothered by police being around." she said. "Those who know they're doing something wrong will be the same who have guilty feelings."

Chief diGrazia called parents "the biggest problem," and charged that "in some cases," parents are "providing and participating" in their children's drug use. "I'm not meaning to suggest that this is the vast majority (of parents) in Montgomery County," he added.

The junior and senior high school students arrested in the Montgomery police crackdown face sanctions ranging from a reprimand by police to confinement in a state juvenile institution, according to officials in the juvenile justice system.

It is possible that a youth brought before the court for the first time for possession of marijuana could be placed in a state institution, according to District Court Judge John C. Tracey, one of two judges in Montgomery County's juvenile division.

"Let's say the family comes in and says: 'We're glad this happened. He uses this drug daily. It has adversely affected his whole life, and we are at our wit's end,'" Tracey said. "This happens sometimes even in the case of a first offender." Under such circumstances, it is conceivable the youth could be placed in a residential home run by the state or a state training, school, Tracey said.

However, both Tracey and Montgomery District Court Judge Douglas H. Moore Jr. stressed that each case is handled individually, with a study of the youth's school record, his family situation and whether he has a drug abuse problem or prior arrest record.

"The court is geared toward rehabilitation, and we have many alternatives to choose from," Tracey said.

A juvenile case also may be disposed of even before it reaches the court. For instance, police youth officers may study a case, decide to reprimand a youth and end proceedings there, or they can send the case on to juvenille court authorities.

DiGrazia has advised these officers to send the case on if they're "on the fence about something." Cases of 11 juveniles already have been forwarded to juvenile court authorities, a police spokesman said.

These authorities may also decide to reprimand the youth, refer him and his family for counseling or send him through a public service job program instead of sending him on to court.

If the youth is sent to court, the judge will first determine in a hearing if he is "involved" in the crime - the juvenile court equivalent of a guilty finding. Then the judge may choose between dispositions ranging from probation, perhaps with counseling, to incarceration in a training school or state forestry camp.