The RRG says "When a player is instructed to reveal cards, he is obliged to show those cards to his opponent. Revealed cards remain revealed until they arrive at the final destination specified by the reveal effect." Murder Cogitator says "Reaction: After a Cultist or Daemon unit you control leaves play, exhaust this support to reveal the top card of your deck. If that card is a [CHAOS] unit, add it to your hand."
If you reveal a card that is not a chaos unit, does it remain revealed until it enters your hand? If you reveal a card using Murder Cogitator, then place it in the bottom 6 cards of your deck using Daemonic Incursion, does it remain revealed while it is in the bottom 6 cards of your deck?