Sorry to hear. Depending on the state, everything passes over to the husband in most instances. While some things may go to probate, it's just a formality. A PITA formality, but one just the same. If they have joint accounts, everything now belongs to whoever is left on the account as they have held "present interest" in such accounts and with the slimmest of exceptions, are not subject to probate and can be transferred immediately. Any life insurance policies with POD to another entity other than her estate is not subject to probate, either and can be remitted immediately.
Still, check with probate laws in your state for more info. Get that will down to the county courthouse and get it filed. Also get the paperwork rolling to open the probate, if applicable, and get the executor/personal representative legally named by the probate judge. For the love of Christ, whoever is executor of her estate it is IMPERATIVE to lock down and secure her possessions. In fact, it's their duty to do so. I agree, whoever is the executor can indeed file a police report as if she had stole from the executor. Because she is in fact, stealing from the estate. As executor, or personal representative, you have a fiduciary duty to the estate. Technically, the executor could be on the hook for missing money/items. Hardly followed up on when it's family, but it's still something that needs to be concerned with.
You also need to get an inventory and approx. street value of everything she owned. Depends on how detailed you want to get it, but things like jewelry, money, cars, or anything in her name only needs to be inventoried. Stuff like purses, alarm clocks, clothes, general non-collectible paperback books, etc., can be lumped into what they call residuary and that is usually divided between the primary heirs with equal shares. Make sure to check to see if there is a residuary clause in the will. If not, the residuaries can suck getting those doled out.
People's true colors come out in these trying times. And we're in the last throes of trying to close out my MIL's estate through probate. I've learned a lot of things about it that I shouldn't have the need to know. If you're not an attorney who does probate stuff, you should never get good at it.