June 13, 2007 -- ABC News has learned that the FBI has targeted a small number of suspected hackers who allegedly took over thousands of personal computers secretly and used them to steal identities and send out massive amounts of spyware and spam.

The FBI said it has identified 1 million computer addresses that have been affected in a scheme called "botnetting" in which criminals turn other people's computers into servers and then use them for illicit activity.

The FBI plans to use its victim assistance program to contact the many people who have had their computers hijacked in this botnetting scheme.

"The majority of victims are not even aware that their computer has been compromised or their personal information exploited," said James Finch, assistant director of the FBI's Cyber Division.

"An attacker gains control by infecting the computer with a virus or other malicious code, and the computer continues to operate normally. Citizens can protect themselves from botnets and the associated schemes by practicing strong computer security habits."

FBI spokesman Richard Kolko added, "The FBI has issued this release and public alert so that consumers will be aware of the threat of botnets and take appropriate security precaution.

"It is difficult without analyzing the individual computer or network to determine if you are a victim of a botnet. In regards to the more than 1 million victim IP addresses uncovered in Operation Bot Roast, the FBI is working closely with industry and other law enforcement agencies to identify the owners of these IP addresses."

To date, the federal government has charged or arrested the following individuals for similar computer fraud and abuse:

James C. Brewer of Arlington, Texas, is alleged to have operated a botnet that infected Chicago area hospitals. This botnet infected tens of thousands of computers worldwide. (FBI Chicago)

Jason Michael Downey of Covington, Ky., is charged with using botnets to send a high volume of traffic to intended recipients, impairing the availability of those systems. (FBI Detroit)

Robert Alan Soloway of Seattle is alleged to have used a large botnet network and spammed tens of millions of unsolicited e-mail messages to advertise his Web site from which he offered services and products. (FBI Seattle)