B.C.'s representative for children and youth says she was disturbed to learn criminal charges were laid against a medical technician on contract for the government who was testing the sexual responses of young sex offenders with sensors attached to their genitals.

"I can tell you I'm shaken by how the issue has come forward," Mary Ellen Turpel-Lafond told CBC News.

Earlier this week, it was revealed that the B.C. government was using a controversial test, called a penile plethysmograph, to gauge how likely young sex offenders were to reoffend.

The government announced it was suspending the tests after the news broke on Wednesday.

The next day, Children's Minister Mary Polak halted the program permanently, saying one of the medical technicians who conducted the tests was charged with sexual assault this month, in a case not related to the individual's government work.

However, Turpel-Lafond said the government's assurance the incident wasn't connected to his work isn't good enough.

"It doesn't reassure me," she said.

Should have been notified 'weeks ago': Turpel-Lafond

Turpel-Lafond only learned about the controversial tests last week — and found out about the charges Thursday when the news was made public.

She was "deeply, deeply troubled" by the news and said her office should have been informed earlier.

"Absolutely, I should have been notified," she told CBC News on Friday.

"I should have been notified weeks ago, and I'm very disappointed by that, and I have expressed that disappointment today to ministry officials."

Polak had said she, too was shocked when she learned of the charges. Turpel-Lafond said that's troubling as it indicates that the ministry doesn't seem to be keeping tabs on its own services.

"The ministry appears to not have known what has been going on with one of its very significant services, or hasn't bothered to notify my office where there's been some serious issues," she said.

The children and youth representative is planning a full investigation to answer what she says are a lot of disturbing questions.

Youths shown sexual images

The penile plethysmographs were being conducted by Youth Forensic Psychiatric Services, part of the Ministry for Children and Family Development. The program was supposed to help develop treatments for sex offenders.

During the test, the young offenders would attach a device to their penis designed to measure physical sexual arousal.

The medical technicians conducting the test would then show the teens sexual images — including ones of adults having sex and naked children and infants — as they monitored their level of arousal.

The subjects were monitored by the medical technicians from behind one-way glass, and their genitals were covered by a sheet during the testing.

Polak has said the program was completely voluntary and required the consent of the subject's parent or guardian. She also said the youths were free to withdraw from the program at any stage.