While the former headmaster of a prestigious and expensive Delaware prep school denies he looked at thousands of child porn images on his iMac, 54-year-old Christopher Wheeler admits no one else had access to his computer.

On Monday, Superior Court Judge Eric Davis found Wheeler guilty of intentionally seeking and collecting child porn, which carries a minimum sentence of two years prison term per charge.

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With 25 such charges filed against Wheeler, a 50-year sentence looms when he is sentenced on March 27, the tentative sentencing date, reports Wdel.com.

The elite school, established by the du Pont family and counts among its graduates DuPont CEO Ellen Kullman and U.S. Senator Chris Coons, distanced itself 14 months ago from the headmaster. The school fired him after investigators found male-to-male sex images on his computer.

The case adds to the more than 200 convictions pursued by the Child Predator Task Force through the testimony of state police Detective Kevin Perna, according to Delawareonline.com.

Wheeler's alibi why his computer had child porn images was that newsgroups he subscribed left 5,000 images or video clips of child porn or erotica on his computer.

However, Deputy Attorney General Abigail Layton pointed out that the headmaster, using the online name "Mr. Filthy," even searched for "gayboystube" in the Internet on the day that authorities confiscated the iMac from his house on Mount Salem Lane in October 2014.

Among the images found on Wheeler's iMac is that of a naked boy, estimated to be 8 to 10 years old, whose hands were tied behind his back while the child was leaning on a table seemingly performing fellatio on an adult since the man had his hand on the boy's head.

Based on these evidence, Layton said the headmaster sought and used child porn for his own gratification. The images on his computer were by design and not mistakenly placed on the device, she stressed.

David rejected the arguments of Wheeler's lawyers and said that the evidence - found in two computers and one hard drive - "proved beyond a reasonable doubt" that the headmaster has a pattern of browsing the internet for child porn.

Wheeler was previously accused of sexual assault on two male teens more than 30 years ago and his adopted son 10 years ago, but he was not charged then.

TagsTower Hill, headmaster, child pornography, Christopher Wheeler, duPont