School officials in Chapel Hill, N.C., are investigating a widespread cheating scheme that included students copying a master key to a high school to get copies of tests and answer keys.

Chapel Hill High School Principal Jackie Ellis sent an e-mail to parents last week notifying them of the scheme, WRAL.com reports.

"Several years ago students obtained a master key to the campus and have had access to most of the rooms at the site since then," Ellis said in the e-mail obtained by WRAL.com. "It appears copies of the master were made and passed down as students graduated.

"Allegedly, students used the keys to go through teacher's offices and obtain copies of tests and answer keys, which they shared with other students," Ellis said.

Some students passed around answer keys to at least one test, even using cell phones to do so, the principal said in the e-mail.

Chapel Hill-Carrboro City Schools spokeswoman Stephanie Knott told the station that some students were disciplined, but she didn't know how many or what type of punishment was meted out.

“At what point do we as parents, or even other kids, stand up and say 'OK, enough is enough,' you know?" parent Danielle Council told WRAL.com. "There's just no reason for all this dishonesty."

The locks on the school's exterior doors are being changed, the principal said.

Click here to read the full WRAL.com report.