MISAWA AIR BASE, Japan — A noncommissioned officer implicated in an international child pornography investigation knowingly kept sexually explicit images of children on his personal laptop computer, a military jury found Tuesday.

In a court-martial here, Tech. Sgt. Jerry Orona was found guilty of possessing child pornography and child erotica. Forensic computer experts testified 40 pornographic images were discovered on a zip file downloaded to Orona’s computer — 32 linked to victims identified by the National Center for Missing and Exploited Children. Investigators also found more than 10,000 digital photographs of children in various stages of undress.

Orona, 36, an aircraft section chief with the 35th Aircraft Maintenance Squadron, could be sentenced to up to 10 years in jail. A five-officer, four-airman jury was to decide his punishment Wednesday morning. Orona was not subject to pre-trial confinement.

Court testimony Monday and Tuesday revealed his name was linked to Operation Falcon, a U.S. government sting. In January 2004, the operation led to charges against a Russia-based child pornography enterprise and a stateside credit card billing service in a global Internet pornography scheme.

Orona’s e-mail account and credit card information were found during an investigation of individual subscribers to the child pornography sites.

That information was forwarded to the Office of Special Investigations at Misawa. OSI agents seized Orona’s home computers and various media materials in March 2004.

Two other U.S. servicemembers in Japan — at Kadena and Yokota air bases — also were implicated, said government prosecutor Capt. Christopher D. May.

“Those guys confessed when confronted” with the evidence, May said. “Orona didn’t.”

He said Orona, who did not testify at the court-martial, never offered an alibi, telling investigators “all I can tell you is I never downloaded child pornography.”

Defense lawyers, led by civilian Phillip Cave, argued prosecutors failed to prove Orona’s guilt.

“There’s nothing to indicate Sgt. Orona was going out and looking for this stuff,” Cave argued Tuesday afternoon.

He suggested Orona could have suffered bad luck — twice: His credit card information could have been stolen and as a result someone else may have subscribed to the illicit Internet sites.

“Where is the e-mail execution … to show the site was in fact visited? It doesn’t exist,” Cave said.

Orona also could have downloaded the illicit zip file unknowingly, Cave said. Jeff Fischbach, a computer forensic expert for the defense, testified about potential dangers of certain search engines that let Internet users download files in bulk without first viewing the images, and that sometimes files are misnamed.

Government and defense computer experts said they could not determine if Orona created or even viewed the zip file, noting that in January 2004, using “Evidence Eliminator” software, he tried to reformat the computer, erasing much of the data memory. Misawa OSI agent Michelle Brown testified that about 30,000 files or images were deleted from the laptop. The zip file was found only through the use of high-tech computer forensics tools.

May pointed to the sheer volume of images found: “You don’t get to argue accidental with that many images,” he said.