An Edison man who used to be a school crossing guard is expected to spend at least 20 years behind bars. Kenneth Christensen admitted he took compromising pictures of a naked child and distributed them and hundreds of other photographs of child sexual abuse over the Internet.

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During his guilty plea proceeding in court today, Christensen, who worked as a school crossing guard in Metuchen, confessed that in 2012, he sent emails to four people. The emails had hundreds of images of child pornography, including sadistic and masochistic conduct. Christensen acknowledged he distributed more than 600 such images.

The 44-year-old Christensen also admitted that some of the files he emailed were pictures he took, including in his own bedroom, of a naked, prepubescent child who was bound in some of the images.

Christensen has pleaded guilty to one count of production of child pornography and one count of distribution of child pornography.

The first count carries a maximum potential penalty of 30 years in prison and a mandatory minimum sentence of 15 years in prison. The distribution count carries a maximum potential penalty of 20 years in prison and mandatory minimum sentence of five years in prison.

Each count also carries a maximum $250,000 fine. Christensen is also required to register as a sex offender. Sentencing is scheduled for Dec. 9.