How can I see in-app purchases made by a family member on my family plan?

For many months now I have been charged small, random charges by Apple. I have emailed them about this about 2 months ago and never received a response. I finally thought that maybe these charges are from someone that is on my family account. Possibly, in-app purchases on games. I mentioned this to the particular member and she says that she "thought" the charges were going to her own credit card, though she never took the courtesy of checking her cc history to be certain. The other person on my family share plan is a minor and I approve all of his purchases. So, I know the charges are not his.

I would like to know how can I actually see what these charges are for so that I can present them to the user I believe is responsible? I have toyed around on iTunes and can only see the apps, tv shows and movies, but not the in-app purchases.

Help!!! I want to see in-app purchase history for all family members on my plan and under my credit card.

Thanks in advance!