A Queensland mother has been ordered to stand trial for the alleged murder of her four-year-old son Taryn O'Sullivan, who was found dead in a backyard swimming pool at Munnborough south of Mackay in August 2021. Tara Marie Richardson is accused of killing the boy and staging his death to appear like a drowning. The 46-year-old will face trial in the Supreme Court in Mackay at a later date.