Does an LLC protect more than just personal assets?

Hi all, I have a
small business (an LLC) that resells gift cards that I buy online. However, the prices of the gift cards that I
buy online are somewhere between 40%-60% off the retail value of the card and I
suspect these cards were acquired illegitimately
or through some type of fraudulent activity, but I
have done some research and couldn`t find any evidence proving that this is so.
Also, the gift cards are available at these same low prices at most online
auction sites like eBay,
S
ell.com and others. My question is, if these gift cards do turn
out to have some fraudulent or maybe even criminal activity behind them, what
type of legal action can be brought against my company for selling the gift
cards to my customers and what steps can I take to further protect myself if
that is the case?