
Lacasse has been with the board since 1986 and has no record.
The school has launched an internal investigation.
All suspects were scheduled to appear in court Thursday afternoon on charges including production, possession and distribution of child pornography as well as sexual assault.
Some 300 police officers have been carrying out search warrants across the province since Monday, provincial police told a news conference.
Investigators tracked suspicious Internet activity between June and October of this year.
Officers seized 28 computers, 1,300 CDs and DVDs, 12 external hard drives and dozens of memory sticks.
A number of homes were searched in major cities including Montreal, Quebec City and Gatineau, across the river from Ottawa.
The arrests came a week after the largest child-porn bust in Canadian history.
Police in Toronto announced that 348 people, including 108 in Canada, were arrested following a three-year investigation into a Toronto film company.