The hackers, an Anonymous-affiliated group known as AntiSec, say that they hope to "embarrass, discredit and incriminate police officers across the US," in retaliation for ongoing arrests of Anonymous members.

AntiSec said that it had compromised servers at Brooks-Jeffrey, a Mountain Home, Arkansas, company that runs a computer store and online marketing firm. Brooks-Jeffrey Marketing builds websites for sheriff's agencies throughout the southern United States. "It took less than 24 hours to root BJM's server and copy all their data to our private servers," AntiSec said in a statement, posted Saturday.

Brooks-Jeffrey could not immediately be reached for comment.

The hackers had already knocked many of the sheriffs' websites offline last week, but on Saturday AntiSec showed that it had gone beyond mere Web defacement, by posting e-mail messages, passwords, social security numbers, credit card numbers as well as messages from confidential informants.

In the U.S., the criminal investigation of Anonymous is being led by the U.S. Federal Bureau of Investigation. The sheriffs' sites appear to hit simply because they are part of the law enforcement community and because a security flaw at Brooks-Jeffrey made them an easy target for the hackers.