State officials are investigating complaints that staff at a special needs residential school gave at least two teenagers unnecessary electric shock treatments after receiving a prank phone call from someone pretending to be from the office of the school's founder.

Initial investigations showed that a former student at the Judge Rotenberg Education Center allegedly called in orders for electric shock treatments on Aug. 26 and officials at the school self-reported the prank call and unnecessary treatments the day after they occurred, Cindy Campbell, a spokeswoman for the state Department of Early Education and Care, said Monday.

"There is still an ongoing criminal investigation," the school's senior counsel, Ernest Corrigan, said. "We are working very closely with investigators."

Nancy Alterio, executive director of the state's Disabled Persons Protection Committee, confirmed that her agency is investigating a complaint that a third victim — an adult — at the a residential facility in Stoughton run by the Rotenberg center also received unnecessary shock treatments after the phone call.

The complaints have also been referred to the state police and the Norfolk District Attorney's Office, Alterio said.

The school treats people with a wide variety of behavior problems, including autistic-like students who have aggressive, self-injurious or destructive behaviors and high-functioning students with psychiatric or emotional problems, according to a description posted on its web site.

"The so-called prank call ... was an isolated, unprecedented incident that occurred more than three months ago," Corrigan said in a statement released Monday. "We immediately reported it to the appropriate state agencies and the local police."

The state Department of Early Education and Care said it investigated a complaint about two youths — ages 16 and 19 — who were given unnecessary shock treatments on Aug. 26 after someone claiming to be on the staff of Dr. Matthew Israel — the psychologist who founded the school — called facility and ordered the treatments.

"We found that there were breaches of internal control procedures that happened in this particular case," Campbell said. "We take this very seriously."

Campbell said the school has submitted a corrective action plan that is now being reviewed by the agency.

"We have modified procedures to assure that an incident of this type cannot occur ever again," Corrigan said.

Two state legislators called on Gov. Deval Patrick to take quick action to put strict regulations in place for the use of shock therapy.

"In a word, this incident is horrifying and it would be immoral for the Legislature and the executive branch not to react strongly and swiftly," said Sen. Brian A. Joyce, who has previously sponsored legislation to ban electric shock therapy.

Kenneth Mollins, a New York attorney who has filed several lawsuits against the Rotenberg center alleging the mistreatment of children at the Canton-based school, sent a letter Monday to Patrick and various state agencies, calling on the state to investigate the complaints, which were first reported by The Examiner newspaper, of Washington.

"The governor needs to take a look and see what's happening here. There is nobody overseeing the store. If somebody can just call and ask that somebody be shocked, there is a significant problem," Mollins said.

The center, believed to be the only school in the nation that uses a two-second skin-shock punishments to change destructive behavior, is no stranger to controversy. It has survived two attempts by the state to close it amid allegations that its unorthodox methods amount to abuse.

Massachusetts was required to pay the center $580,000 after it unsuccessfully sought to close the school following the 1985 death of a 22-year-old student who suffered a seizure while restrained and forced to listen to static noise.

More recently an investigation was ordered to determine if a shock device malfunctioned, causing burns to one student. The center also agreed to stop referring to staff members as psychologists if they have not been licensed with the state.

On Monday, the center defended its use of the intensive treatment methods, saying they are used in a minority of cases as part of overall therapy for "very deeply emotionally disturbed young adults."

The procedures are applied "only after obtaining prior parental, medical, psychiatric, human rights, peer review and individual approval from a Massachusetts Probate Court," Corrigan said.