turn king's/queen's evidence

if someone who has been accused of a crime turns king's evidence, they give information in a court of law about other people involved in the crime in order to have their own punishment reduced.

She was given a lenient sentence in exchange for turning king's evidence.

• come within an ace of doing something
• come within an ace of something
• come within an inch of
• come within an inch of doing something
• come within a whisker of
• come within a whisker of doing something
• come within a whisker of something
• come with the territory
• comings and goings
• commit something to memory
• commit to memory
• commit to memory something
• common ground
• common-or-garden
• common touch
• compare apples and oranges
• compare notes
• conk out
• connect the dots
• contradiction in terms
• contrary to popular belief
• contrary to popular opinion
• conventional wisdom
• conversation piece
• cook goose