The Rockville Library will do that search for you, or at least they used to.
Here is their contact information:
Montgomery Co. Public Libraries
Ask-a-Librarian Service
21 Maryland Ave.
Rockville, MD 20850
240-777-0001
Call them and they'll look up the obits. in the newspapers they have on microfilm, and they'll send whatever they find to you via email.

Also, the Washington Post newspaper has a searchable archive on line. If they have the obit. in their index you would need to register with them and pay a small fee to see the actual obit., so calling the library is usually a better idea. But here's the link to the archive search page in case you want it:
http://pqasb.pqarchiver.com/washingtonpost/advancedsearch.ht...
Good luck.