Dic: Heads will roll

• When the company's year-end results are known, heads will roll.
• Heads will roll when the principal sees the damaged classroom.
• If the accident was caused by company negligence, then heads will roll.

If you say that heads will roll as a result of something bad that has happened, you mean that people will be punished for it, especially by losing their jobs.

... http://idioms.thefreedictionary.com/heads+will+roll, Cobuild