I gather that the worry behind your question is whether the dead really have "possessions" to be stolen: How can a dead person "possess" something? After all, they can't hold it, see it, use it, etc. But it's worth keeping in mind that stealing amounts to taking something that properly belongs to another — something in which that person has a property right. And having a property right and all that entails — having the right to preclude others from using an object, most importantly — does not seem to turn on our physical relation to an object. Whatever moral claim I have on my house, for example, doesn't turn on my actually being present in the house: My property right in the house is, as Kant put it, a matter of "intelligible possession". Others don't have the moral permission to occupy or use my property even when I am not using it or am not in physical possession of it. So I don't see that the fact that the dead are, well, dead and so can't possess their property in a literal sense is any barrier to their having property rights, and so it seems reasonable to think that the dead could have their property rights violated, by (for instance) others stealing their property.
Notice that certain of our social practices seem to depend on the notion that the dead have property rights: The clearest are wills, which provide legal direction regarding how to allocate a dead person's property, and organ donation, which can be understood as providing legal direction regarding what to do with a certain kind of property: one's own organs.
So I don't see any deep conceptual barrier to the dead having property that could be stolen from them. Perhaps the more intriguing question in this area is why the dead retain the property rights they had while alive -- but that's a question for another occasion perhaps.