In June 2005, I was the victim of online credit card fraud which was investigated, almost immediately, after I reported the incident to the proper authorities, including my financial institution, the police department, Attorney General, the FBI, and the FTC.
In one of the transactions, the alleged "crook(s)" used my credit card to purchase from Abercrombie.com eight  Abercrombie and Fitch Gift Cards in the denomination of $50.00s. These were mailed to the alleged "crook(s)" in Oak Lawn, Illinois, to a drop box. Unluckily for the "crook(s)," the drop box had been under surveillance for some time, due to the variety and quantity of packages being received. The postal inspector secured the drop box key and detained 2 college students. Supposedly, the students had already obtained false IDs and were busy reselling the merchandise on auction sites, and sending a percentage of the profits back to a Nigerian connection!
You too can make a difference if you have been a victim of online fraud. I did not waste any time contacting all the proper authorities; time is of the essence.
For filing a report online with the FBI, here is the link: http://www1.ifccfbi.gov/index.asp.
Read more about my experience in To Catch a Thief!