The April 13, 1998 issue of Inter@ctive Week (p. 30.) reports that the 
Community Wide Web of Stockton California, an ISP, was attacked in
a retaliatory fashion on March 12.  Marrya VandeVen, general manager of
the ISP, found a child-porn site, tracked its origin in New Mexico and
notified both the FBI and U.S. Customs agents.  That's when the
retaliation began.  While the case itself is interesting, what's even more
interesting is a comment from Ms. VandeVen:

"Somebody had hacked our system, and the backups wiped themselves clean ...."