@MissionMan Appears you have very little faith in the police's abilities...
The site that you linked above is NOT a government agency. Whilst it purports to do the "right thing" by providing some great links for who you SHOULD go to - IE the police - it then offers a list of alleged sexual offenders. The site even says it does not condone anyone acting against the people on the list (no doubt to try avoid any legal action). This is NOT where you should be providing any information, because the mako site IS vigilantes. They are taking action into their own hands to provide what they claim to be factual information about sex offenders. No law enforcement agency in Australia makes these lists public.
(I believe at some point (years ago) they somehow obtained a copy of an "official list", but there's nothing to say it is still accurate, and there's nothing to say that any entries they may have added are accurate. Imagine if your name or even just your address ended up on that site...)
Your local police station is the best place to take this information, so they can investigate the matter, and hopefully stop it happening to anyone else.