OAKLAND (CBS SF) — A Lawrence Berkeley National Laboratory employee was convicted on Thursday of possessing child pornography, according to federal prosecutors.

David Busby, a 60-year-old Richmond resident, was convicted by a jury in U.S. District Court in Oakland following a three-day trial, according to the U.S. Attorney’s Office.

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Busby was arrested after a network security analyst detected Internet traffic indicative of child pornography on the National Energy Research Scientific Computing Center computer network on April 20, 2010, prosecutors said.

The traffic was traced to a single laptop being used by Busby, a computer support employee at the Lawrence Berkeley National Laboratory and a part-time employee at NERSC.

After Busby’s laptop and other work computers were confiscated, he told investigators that he did download child pornography on two of his work computers, prosecutors said. He said he would store the images for a period of time and then delete them.

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At his trial, Busby said he accidentally downloaded the child pornography while trying to access legal child modeling sites.

Investigators determined around 1,400 images of child pornography had been deleted from Busby’s computers.

Busby was remanded into custody after his conviction on Thursday. He is scheduled to be sentenced on Dec. 17.

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