A computer vandal broke into The New York Times' Web page and left a message supporting imprisoned hacker Kevin Mitnick.

The FBI is investigating.The Web page was down for 12 hours after an editor noticed the tampering Sunday morning, said Nancy Nielsen, a Times spokeswoman.

Martin A. Nisenholtz, president of The New York Times Electronic Media Co., speculated that the attack was timed to coincide with the high demand for cyberspace following the release of Independent Counsel Kenneth Starr's report on President Clinton.

"This is a much more destructive weekend to be doing this than normal," he said. "We were running 35 percent above normal on Saturday, and typically Sunday is twice as big as Saturday."

The site records 150,000 visits on a typical Sunday, the Times said.

The infiltrator claimed to represent a group calling itself HFG, or "Hacking for Girlies," and ridiculed several members of the Times staff.

It took special aim at Times reporter John Markoff, who wrote "TakeDown," a book detailing the search for Mitnick. Mitnick has been imprisoned on computer-related fraud charges since 1995.