Try searching the Dodgy File's name in Google, with 'Removal' afterwards.
So, for example, I can think of two. One which states "Hey is this you in the picture" and a link, which links to the downloading of a virus. And another called a 'Block Checker' which automatically contacts all of your contacts asking them to download the Block Checker.
I do not personally know how to remove them, but if you try Google-ing them, that might work.