Your search for "Thorough Investigation 12" revealed the following:
Thorough Investigation (AFC) from Forgotten Realms Commander, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Aaron J. Riley Card Text:Whenever you attack, investigate. (Create a colorless Clue artifact token with "2, Sacrifice this artifact: Draw a card.")Whenever you...
Thorough Investigation - Extended Art (AFC) from Forgotten Realms Commander, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Aaron J. Riley Card Text:Whenever you attack, investigate.Whenever you sacrifice a Clue, venture into the dungeon.