Steven Unthank is a private citizen.
In Australia criminal charges can be brought against a person or other entity in three ways. 1) By the police. 2) By the office of Public Prosecutions (like a district attorney). 3) By a private citizen, if the citizen puts the work into investigating and preparing a case. The court will then examine the case and decide if it has merit. If it does, the government prosecutor will take it over.
He is an ex-Witness who is concerned that the Watchtower has refused to comply with the Working With Children Act. He has done a tremendous amount of work in having 5 different Watchtower entities charges with 7 criminal counts each. So far, all counts are still in effect.
His web site is here,
http://jwnewsnetwork.wordpress.com/2011/07/26/press-release/
A long thread is here,