NSW cult leader William Kamm and co-accused Sandra Mathison face grooming trial

Consensus Summary

A judge-alone trial is underway in Sydney’s Downing Centre District Court, where William Kamm, 76, and his wife Sandra Susan Mathison, 60, are accused of grooming a young girl for more than a decade. The complainant, now in her early 20s, alleges that Mr Kamm, the self-proclaimed leader of the Order of Saint Charbel cult near Nowra, began grooming her when she was aged six. According to both ABC and The Guardian, he allegedly told her it was her ‘mission from God’ to become his ‘main queen’ and bear 45 of his children to repopulate the world after an apocalypse. Ms Mathison, also one of Mr Kamm’s ‘queens,’ allegedly facilitated their communications while he was in custody for unrelated matters in 2011, with calls continuing after his release in late 2014.

The grooming allegedly took place over a period spanning the complainant’s childhood, from age six to 16, with Mr Kamm maintaining frequent contact, including calls at least twice a week. The Guardian reports the abuse occurred between 2010 and 2020, while ABC emphasizes the duration as ‘more than a decade.’ The complainant moved to the cult’s Bangalee property in 2019, but plans for her first in-person meeting with Mr Kamm were disrupted by Australia’s COVID-19 lockdown in 2020. Both outlets agree that the pair were arrested in September 2024 after the complainant reported the matter to police in 2023.

The complainant testified that Mr Kamm presented his demands as part of a divine mission, using religious language to justify his actions. ABC reports that she initially felt excited about the ‘mission’ but later experienced anxiety, panic attacks, and suicidal thoughts, particularly after moving to the cult grounds. She described feeling ‘dirty’ after Mr Kamm allegedly made inappropriate suggestions, such as trapping her in closets. The Guardian highlights that Ms Mathison allegedly reinforced the complainant’s ‘marriage’ to Mr Kamm, warning her that the ‘devil’ would try to stop it and that she could not associate with other boys.

While both sources agree on the core allegations, ABC provides additional details from the complainant’s diary entries, including her relief when Mr Kamm returned to custody in 2022 and her confrontation with him about his sexual advances. The Guardian, however, includes a specific allegation not mentioned by ABC—that in March 2020, Ms Mathison allegedly suggested the complainant could receive Mr Kamm’s sperm in a cup to impregnate herself. The framing also differs slightly, with The Guardian emphasizing the cult’s apocalyptic beliefs more explicitly, while ABC focuses on the psychological manipulation and the complainant’s emotional distress.

The trial, presided over by Judge Nicole Noman, continues with both defendants pleading not guilty to charges including grooming a child under 14 and breaching supervision orders. ABC notes that the complainant’s evidence has centered on the cult’s structure, Mr Kamm’s self-proclaimed role as a prophet, and the ways in which she was isolated and controlled. Legal representatives for both Kamm and Mathison have challenged the Crown’s case, with Kamm’s barrister arguing he never physically met the complainant. The outcome of the trial remains uncertain, but the prosecution’s case relies heavily on recorded calls, letters, and gifts allegedly exchanged between the defendants and the complainant.