DENVER (CBS4) – The Denver Sheriff’s Department is looking into an anonymous letter sent to the local media. It claims answers to a department exam were given out before hand.

The department says the letter is from an unknown deputy. The writer says he was given answers by a superior to a written promotional exam. The deputy says he passed the answers on to others but then felt guilty and alerted the media.

The sheriff’s department is promising a thorough investigation.

It’s the second high-profile cheating investigation this month in Colorado. Last week the state stopped certifying new firefighters indefinitely after a proctor who works for the fire department in Greeley allegedly gave firefighters an old test as a study aid.