PLAINFIELD, Illinois [Suburban Chicago News] -- Could your computer become a hacker's storage vault for child porn, unbeknownst to you?

Some say it can happen -- and has.

One Plainfield man facing child pornography charges thinks it happened to him.

Kevin F. Plachta, 45, of 16125 Vintage Drive in Plainfield, said he may have inadvertently downloaded a computer virus, or was the victim of a hacker, but he didn't knowingly download child porn.

About a year ago, the FBI seized his household computers, saying they had reason to believe there was child porn on one of them, Plachta said.

They took three computers and eventually returned two, he said. The FBI refused to return the third because they said there were questionable images on it, Plachta said.

Plachta was arrested Nov. 14 on two counts of child pornography.

The complaint filed with the Will County State's Attorney's office accuses Plachta of having a photo and a partial video depicting child porn on his computer.

In an interview last week, Plachta maintained his innocence and said he was likely a victim of a virus or a hacker that planted the images on his machine.

Could an unsuspecting computer user aid a child pornographer by accidentally downloading their handiwork?

It's not likely, according to Dave Margliano, computer crimes investigator for the Will County State's Attorney's Office.

Computer viruses are often accidentally or unknowingly downloaded, he said -- not pictures or movies of child porn.

"I have never found that situation where pictures (or movies) are downloaded to your computer without your knowledge," Margliano said. "I've been doing (computer investigations) since '98 and I've had well over 300 cases. Never, never, never has that happened.

"And, if something was on your computer, you would certainly have knowledge if you were making CDs or DVDs. There's absolutely, positively, 100 percent no way you could have that media and not know what's on it," he said.

In Will County, child pornography cases take some time to build, Margliano said. Evidence of multiple downloads and other investigation is required before authorities will try to bring charges, he said.

"Very few (child pornography cases) go to trial because the evidence is so overwhelming that the defense attorney certainly does not want a jury to see what their client had or was doing," Margliano said. "They certainly don't want a judge to see the evidence."
Real-life cases
Documented cases of hacked computers -- and people being wrongly accused when the hackers' evidence is discovered -- do exist.

Matt Bandy of Phoenix was 16 when he was charged with nine counts of child pornography in 2005.

Authorities said the Bandys' computer had accessed a Yahoo! account where there was child pornography. There were also images on the computer, along with hundreds of infected files that would allow a hacker to remotely hijack the computer.

A forensic computer expert hired by Bandy's family said Matt, who had admitted he looked at adult pornography online, didn't upload the child porn images.

Instead, the expert believed the Bandys' computer was taken over by a hacker.

Bandy and his parents took multiple lie detector tests and underwent psychological evaluations as part of his defense.

Bandy ended up pleading guilty to a reduced charge of distributing obscene materials to minors -- which stemmed from his showing a Playboy magazine to his underage friends.

Plachta said his case is similar to Bandy's and mentioned the family's Web site, www.justice4matt.com.

The site includes examples of other people who were charged with crimes after their computers were allegedly hacked.

Jonathan Bernstein, president of Bernstein Crisis Management in Sierra Madre, Calif., helped the Bandys bolster their case in the media.

Since Bandy's story became public -- and was featured on ABC News 20/20 -- it has been "loosely" used as a defense by a number of child pornography suspects, he said.

"The Bandys and I were bombarded by e-mails after his case (became public), saying their case was the same," Bernstein said. "Rough guess, 75 percent said they wouldn't do psych tests or polygraphs. I think a lot of people use Matt's case without going to the lengths the Bandys did."