Every day, the popular uTorrent client is used by the masses to legally or illegally download all manner of torrent files. With that comes the risk of computer infections or a lawsuit from a copyright holder.

A suburban Illinois man got way more than what he bargained for after the history buff downloaded files on World War II ordnance. What 40-year-old Wojciech Florczykowski of Schaumburg got in 2011 was an extreme visit from the FBI and ultimately a charge of child-porn possession.

"The FBI descended on his home with bomb-sniffing dogs and a diffusing team and the whole shebang," his attorney, Lawrence Lykowski, told Ars on Friday.

His client was acquitted Wednesday. His defense was one routinely uttered by those accused of possessing child porn: "I didn't mean to download that." And clearly, Florczykowski was telling the truth.

"There was no evidence to suggest the defendant intended to possess child pornography," Cook County Judge Thomas Fecarotta said when acquitting Florczykowski.

His nightmare began three years ago when his superiors at DLS Electronic Systems discovered a folder on his laptop called "anarchy." The folder contained files on how to build explosive devices. Federal authorities ultimately declined to prosecute, but almost three years later, Cook County prosecutors went ahead with a child pornography prosecution, as some of those files contained illicit images of children—139 in all.

"What I discovered was completely disgusting. I was not looking for this stuff," the man testified at his bench trial. He said he deleted the files but got laid off from his engineering job before getting the chance to scrub his work computer.

As it turned out, the illicit porn he downloaded in 2011 was mixed into files he downloaded to satisfy his interests in World War II battlefield memorabilia. According to his attorney, Florczykowski often returns to his home country of Poland with other military history nerds and searches battlefields with metal detectors.

"They look for artifacts from World War I and World War II," Lykowski said. He said his client has found land mines and hand grenades.

The case should never have been brought, Lykowski added. "He told them it was an unintentional download. This case has been preying on him and his wife's mind while the case has been pending."

Supporting Florczykowski's claims of innocence was that forensic experts on both sides of his case found zero proof that he ever searched anywhere online for kid smut. An expert for the prosecution also testified that it's also possible that child porn could be inserted into files not marked as kid smut, Lykowski said.

Florczykowski was facing a maximum seven years in prison if convicted. He also would have been required to register as a sex offender for life.

"I don't know how you protect yourself from something like this, to tell you the truth," Lykowski concluded.