David Kernell, 20, has not returned repeated phone calls or e-mails from the AP since last week. He is the son of state Rep. Mike Kernell, a Memphis Democrat and chairman of Tennessee's House Government Operations Committee. The father declined last week to discuss the possibility his son might be involved in the case.
"I had nothing to do with it, I had no knowledge or anything," Mike Kernell told the AP.
"I was not a party to anything of this nature at all," he added. "I wasn't in on this and I wouldn't know how to do anything like that."
The apartment the FBI searched is in a complex about five blocks from the University of Tennessee campus in a neighborhood popular with students. No one around the complex Monday knew David Kernell or saw the FBI agents over the weekend.
A hacker last week broke into one of the Yahoo Inc. e-mail accounts that Palin uses, revealing as evidence a few inconsequential personal messages she has received since John McCain selected her as his running mate. The McCain campaign confirmed the break-in and called it a "shocking invasion of the governor's privacy and a violation of law."
Palin used "gov.sarah" in one of her Yahoo e-mail addresses she sometimes uses to conduct state business. The hacker targeted her separate "gov.palin" account.
After the break-in, a person claiming responsibility published a detailed chronology of the hacking on the Web site where the break-in was first revealed. That person identified his e-mail address as one that has been linked publicly to David Kernell.
Mike Kernell, 56, is known for his liberal stance on state issues in the Legislature. He was among a handful of Democrats to vote against the Tennessee governor's health plan because he said it wasn't expansive enough. He also opposed a recent increase in the cigarette tax because he felt the proceeds should have been directed toward health care instead of education.
Kernell was also among five House members who voted against a sweeping overhaul of state ethics laws in 2006. He said the new law's limits on cash contributions hurts candidates seeking smaller donations.
Kernell has a straight-laced reputation among his colleagues.
"Mike Kernell is your quintessential Boy Scout," said state Rep. John Deberry, another Democrat. "Mike follows the rules. He will almost get on your nerve as far as making sure things are done by the book."
"If Mike had known anything about this, he would have had a fit on his son," Deberry said. "When I saw his reaction when he first heard about it, the absolute fear and shock that was on his face, I realized then he had absolutely nothing to do with it."
Experts said the hacker apparently left an easy trail for investigators.
"He might as well have taken a picture of his house and uploaded it," said Ken Pfeil, an Internet security expert. "He should have just set up a big beacon that said, 'Here's my house,' or confessed. If they can't catch this guy based on all the information posted on the Web then all bets are off."
The hacker described guessing correctly that Alaska's governor had met her husband in high school, and knew Palin's date of birth and home Zip code. Using those details, the hacker tricked Yahoo's service into assigning a new password, "popcorn," for Palin's e-mail account. What started as a prank was cut short because of panic over the possibility the FBI might investigate, the hacker wrote.
The FBI and Secret Service are now investigating.
The law enforcement officials confirming the search spoke on condition of anonymity because of the sensitivity of the investigation.
In Washington, Justice Department spokeswoman Laura Sweeney confirmed Monday only that the FBI conducted "investigative activity" late Saturday and early Sunday in Knoxville related to the case.
David Kernell is an economics major at the University of Tennessee there.