case closed

Expressing finality, that that preceding material is meant as final, not subject to amendation or variation.
- 2007, Ripple Effect‎, page 13:
  […] he would no more tell a grunt in uniform what he was really thinking than he'd drop his pants and wag the weasel at a formal diplomatic function.
  Some things were simply not done by professionals. Full stop. Case closed.
- 2011, Dominick Ricca, "The Salvation of Satan", in Would You Like to Be White? and Other Stories, Xlibris (self-published), →ISBN, page 403 :
  "And I your God say no angel of mine will ever marry a female human being. And that is final!"
  
  "Positively final?" I asked in a firm, steady voice.
  
  "Yes! Doubly positively final! Case closed!"
Used other than figuratively or idiomatically: A case is closed; specifically, a police investigation or similar is resolved.
- 2009, Brad Thor, The Apostle‎, Atria, →ISBN:
  The bodies of the deceased were removed from the scene to the Suffolk County medical examiner's office in Hauppauge. […] As you can see from the report, Nikki Hale was the only one who was impaired. Case closed.

a case is closed

English