There is a quest forgot the city where the countess had a picture stolen.

you talk to 5 different people and Im ready to accuse someone but she says I need evidence... can anyone help?

You need to ,

1. go to the dining room, and search the carpet.

2. go to the second floor on left side, and search for that womans table (or what is it called).

Then if I can remember right, you'll be able to accuse the woman.

I had a bit of trouble with this quest too. You have to ask the five people all the appropriate questions (don't accuse anyone just yet). Then just look around for evidence. You'll find paint on the carpet in the dining room off the main hall (this was hard to find) and you'll find paintings hidden behind boxes in one of the storage area tower things. You can then go to the woman's room (upstairs to the left from the main hall if I remember right) and open her lectern (which you couldn't before) and you'll find painting supplies. Then accuse her, and go from there.