Forum:All Tombstones Missing! (The Sims 3)

I was trying to install this gravyard I made into The Sims 3 Store, and it said that the sims in the lot wee going to stop what they are doing. I installed the graveyard and when I returned to my game, all the tombstones of the sims that I have intentionally murdered have disappeared. It said that all the tombstones were in the Family Inventory, but there was not a tombstone in there. Was it my fault that the tombstones were gone, is it a glitch or a bug, or was it karma for killing all those sims?