Can the police stop heirs from removing property from the dead persons house before the will is even filed for probate?

In theory, taking property from another (the estate), with intent to permanently deprive the other of its use, is called "theft" and the police can become involved.

In practice, however, the heirs can claim it is a civil (not criminal) matter between themselves ("so, sue me and prove it isn't my stuff"), and the police will be excused from enforcing any criminal laws, absent any evidence of a crime. They can, however, become involved in "preserving the peace" where anyone is making a public disturbance.

The middle ground would involve hiring private security to watch stuff (and keep records of anything still there or as it leaves), changing the locks, and demanding an immediate accounting for anything removed from the house without the necessary permission of the executor. Absent any accounting in reply, the executor could sue for the return of all missing property.