Zimmerman is expected to be sentenced to between 12 and 20 years in prison, which also include offences of making child pornography, stalking, procuring and grooming teenage girls via social media. He contacted them by "random" adding them to his Facebook and MySpace pages.
In all, Zimmerman has pleaded guilty to 87 charges involving crimes against 55 underage girls, accepting a plea deal which had the federal and state charges cut from in excess of 200.
Zimmerman is now regarded as a landmark case in predatory cyber crimes.
He was charged with illicitly having sex with seven underage girls - including two of whom stated to police they had lost their virginity to him.
Up to 40 other teens discovered on Zimmerman's computer hard drives refused to speak with investigators or were not allowed to by their parents.
Twenty others may have been procured or groomed for sex, and other girls' images could not be identified.
Legal loopholes have also prevented Victoria Police charging the sex fiend with offences they believe he committed outside Victoria.
Zimmerman is suspected of two sexual assaults interstate, including the alleged rape of an Adelaide minor.
Sources say up to 1900 girls were contacted by Zimmerman, who sent more than 60,000 messages over a two to three-year period.
The 26-year-old Frankston man, who raided the MySpace fan site of a popular band he managed - The Getaway Plan - to stalk girls and then their online friends is on remand and living in a prison protection unit.
Anthony Dowsley From:
Herald Sun December 15, 2011