The price of a free lunch

Every week, Chang pulled a business card out of the fishbowl and the winner got a free lunch at The Happy Dragon.
Every so often, another hand would dip into the fishbowl and draw a business card. But they never got a free lunch.
They found Mary’s body in the dumpster the next day. The same with Steve, Lynn, Arthur, and Jose. Sixteen in all.
One day, the killer reached into the bowl and got his hand wet.
No business cards. Just a goldfish.
Sure, there is such a thing as a free lunch, but it’s not worth the risk.