1. I didn’t take the box of candy.
2. I have never stolen anything.
3. Dennis did it.
4. I didn’t take the box of candy.
5. I’m rich and I can buy my own candy.
6. Linda knows who the crook is.
7. I didn’t take the box of candy.
8. I didn’t know Linda until this year.
9. Dennis did it.
10. I didn’t take the box of candy.
11. Linda did it.
12. Ivan is lying when he says I stole the candy.
13. I didn’t take the box of candy.
14. Sylvia is guilty.
15. Ernie can vouch for me because he has known me since I was a baby eight years ago.
Not as hard as it sounds!
If Ivan was the thief, then he told more than one lie.
In the same way, we can exclude Ernie, Dennis, and Linda.
So Sylvia is the thief, and the false statements are #3, #4, #9, #11, and #15.