Assuming that you or your relatives were not able to find a will in the more obvious places at your mother-in-law's home and office--desk drawers, file cabinets, closets--there are a number of other places you might try.

Some people lock away their wills in safe deposit boxes, even though survivors often do not have easy access to such a spot; check with local bank officials.

If you know your mother-in-law hired an attorney to help with any particular matter, you may also ask if that attorney helped with or knows of a will. And if you don't know whether she consulted a lawyer in her lifetime, you may consider putting a notice in a legal newspaper or state bar publication asking for an original or copy of your mother-in-law's will.

Finally, check with the local probate court. While it is rare, some people file a copy with such courts while they are still alive, just for safekeeping.