There is probably nothing you can do. Your question assumes that the authorities know who these people are, which they probably don't. It assumes they are in the U.S. rather than somewhere else in the world. It assumes that these people have verifiable assets that can be attached, which they probably don't.
I'd say best case scenario is they are caught which even that is unlikely and put in jail so they can't continue to do this to other people. See filling out a police report does'nt guarantee you'll get your money back.
I'd say chalk this up as a loss and reconsider next time you decide to purchase something over the internet with a company you are not familiar with.
To all who read this, doing business over the internet is risky business in my opinion unless you are doing business with a reputable company. Generally you would not purchase a produt or service from a company you are not familiar with unless you were referred by a friend or family member who have had a good experience. An internet company should be approached with the same caution and forethought.
[Edited by David J. Miller on 12-08-2000 at 11:04 AM]