I just thought of another option - move the corposes outside the cell walls until you want them to appear, then move them back.
1. Place a piece of floor tile (or 2 or 5) just Above the ceiling of where you have them placed.
2. Initially put the bodies on those new floor tiles above the room (so the player cannot see or interact with them).
3. When you want them in play, simply move the corpses vertically downwards to exactly where you want them in the cell - and you accomplish the same effect.
This is essentially the same thing as the secret door script idea that I use, except your doing the move only once and in only one direction (to simplify the code).
The pseudo-code would look like:
FLOAT StopPositionZSET StopPositionZ to DeadBody.GETPOS Z - 100DeadBody.SETPOS Z StopPositionZ
This would move the body downwards by 100 units. You'll have to experiment with this in-game to find the exact value that you need to move the bodies downwards, but once done the body will eeriely float downwards througth the ceiling and into position.
Miax