Police have arrested three juvenile boys and identified at least five victims in multiple cases of sexual assault and misconduct at the Hawaii School for the Deaf and the Blind since 2006.

Michael Green, the attorney representing one of the parents of the victims, alleged Friday that besides school authorities, top officials at the state Department of Education were told of the allegations as early as 2009 and did nothing.

Meanwhile, Sydney Dickerson, longtime principal of the school, was placed on department-directed leave on July 12, and the school is now being headed by an acting principal, said department spokeswoman Sandra Goya. Dickerson, who has been at the school since 1993, is president of a national association of deaf schools.

At issue are allegations that students at the Kapahulu school forced others to engage in sexual activity. At least some of that activity was criminal, police said.

Lt. Randall Akau of HPD’s Criminal Investigations Division said three juvenile males, either current or former students, have been arrested on sexual assault charges as part of the investigation since the beginning of the year. The latest arrest occurred Thursday. The charges include first-degree sex assault, the most severe of sex-related offenses.

Police have identified at least five victims who are or were students at the school, Akau said.

Incidents are believed to have occurred as early as 2006, he said. At least some victims lived in the school’s dormitory, he said.

The investigation is continuing, Akau said, and there might be other suspects. None are adults, "not up to this point," he said.

Akau said police learned of the allegations when students came forward earlier this year.

The Hawaii School for the Deaf and the Blind, which had an enrollment of 67 students in 2010-11, is a public school under the Education Department.

The department said in a statement that it is cooperating with police and has initiated its own investigation.

The department said "takes its responsibilities seriously to safeguard the health, safety, and welfare of its students, and is committed to investigate all claims of inappropriate behavior."

"At the onset of the investigation, immediate steps were taken by the department to increase security and safety measures on campus to ensure the safety and well-being of students and employees."

Attorney Green said he has documents proving top department officials knew of the allegations as early as 2009 and did nothing.

Green said he has spoken to the parents or guardians of at least half a dozen students or former students, some of whom have moved to the mainland because of trauma caused by the sex assaults.

"It’s a zoo," he said. "It looks like for a number of years, and I’m talking before 2009, there was sexual contact among many, many students … and people at the highest levels of the DOE knew it."

Green read to reporters a copy of a letter received by parent from a top education official he would not name, thanking the parent for bringing the issue forward.

Pat Hamamoto, schools superintendent in 2009 and now principal at Saint Louis School, could not be reached Friday.

Green said it is outrageous that criminal sexual activity may have been allowed to take place on a campus where students have disabilities that can make them more vulnerable. "If you have the slightest hint, you don’t wait until somebody comes forward and the police talk about kids being raped and sexually assaulted," he said. "You don’t wait a second in protecting your children."

Green said cases involving one or possibly two of the suspects have already been adjudicated in Family Court. But officials with HPD, the prosecutor’s office and the Judiciary declined to verify Green’s claim, citing the need for confidentiality in cases involving juveniles.

Green said he is looking into filing a class-action lawsuit against the state.

Parents have told him about inappropriate sexual behavior that took place in school bathrooms, school buses and rooms in the campus dormitory, Green said. "There was no security, and if there was, it was woefully inadequate," he said.

Green reiterated that he believes as many as 30 or 40 students, possibly more, may have been victims.

Lou Erteschik, staff attorney for the federally funded Hawaii Disability Rights Center, said advocates in his office have assisted over the last few years "four or five kids" from the school who were victims of inappropriate and possibly criminal sexual behavior. He said he could not provide other details.

Several parents contacted Friday by the Star-Advertiser said they were stunned to learn details of the investigation.

Stella Chang, whose 13-year-old daughter attends the school, said parents received a letter from the DOE in late July, prior to Monday’s school opening. The letter notified them that Dickerson was put on leave but did not explain why, she said.

Chang said the letter also said the department wanted to make sure the school was a safe environment. Chang said she also received a call from a department employee saying each parent was being contacted.

She said she was surprised when she heard the news about the nature of the investigation. "We had no idea, absolutely no idea."

Chang said the students are excited about the new programs, and her child has been progressing steadily.

Charlie Morris, whose 13-year-old niece attends the school, was shaken by the allegations. Morris and his wife, Michele, of Ewa Beach, have guardianship of their niece. "We’re going to be keeping a close eye on this school, and hopefully things change for the better," Morris said. "It was shocking to hear. These are years we’re talking about. This is just unbelievable."

Michele Morris was a teacher at the school in the 1990s and said she doesn’t understand how the assaults could have been going on for so long. "How was this able to happen?" she said, adding that as a teacher she was trained that "anything minute that you suspect you have to report."

"I’m just shocked that this could have gone on like this without being reported."

The allegations come as the school is undergoing an academic overhaul as one of 14 persistently low-performing schools statewide. Parents have long lauded the campus as being an important resource for the deaf community, whose students often feel isolated in mainstream education settings.

"What’s sad is that there is so many good things at the school," Michele Morris said. "The communication through ASL (American Sign Language) is good. There’s good technology."

Star-Advertiser reporters Gary T. Kubota and Mary Vorsino contributed to this report.

Hawaii News Now Video: Deaf and blind students allegedly involved in multiple sexual assaults