Alberta Education and Edmonton Public Schools are investigating rumours that someone stole a high school diploma exam and distributed it to others.

School board officials say the rumours involve a number of schools and relate to a Pure Math 30 exam given Friday.

"Our understanding is that someone may have obtained a copy of the diploma exam in advance of the test and was either giving it or selling it to others," said Cory Sinclair, who speaks for Edmonton Public Schools.

The exam is critically important to students, Sinclair said, because it represents half the final mark in the course.

"I think the investigation will definitely get to the bottom of it, and determine what schools and what boards may or may not have been involved," said Sinclair, adding that every high school in the Edmonton district has been advised of the investigation.

Education Minister Dave Hancock told CBC's Wildrose radio program a criminal investigation is possible, but there is little chance the exam would be given over again if it's discovered it was stolen and distributed.

"There's mechanisms in place with respect to data analysis which can determine with a fairly good degree of accuracy if there's been areas that need to be investigated with respect to whether cheating has occurred," said Dave Hancock.

"In the vast majority of circumstances, of course, that wouldn't be the case."