Collect evidence

Collect evidence is a keyword action introduced in Murders at Karlov Manor.
==Description==
Collecting evidence involves a player exiling any number of cards from their graveyard with combined mana value equal to, or greater than, N (the evidence number).
Collecting is done as a cost, mechanically similar to Bargain or Kicker, where doing so is optional and gives a bonus to the spell if "evidence is collected". It can also be used on Ward costs.
===History===
Collect evidence was also used in Ravnica: Clue Edition, and made a quick reappearance in Modern Horizons 3 where is was used as an alternative cost for Bestow on <c>Detective's Phoenix</c>.
==Rules==
==Rulings==
*If you can't exile enough cards to meet or exceed the required mana value, you can't choose to collect evidence at all. 
*Once you've announced that you're casting a spell, players can't take actions until you've finished doing so. Notably, opponents can't try to remove cards from your graveyard to stop you from collecting evidence.
==Example==
==References==