The case of the 12-year-old school girl Tiahleigh Palmer who was molested by her foster brother and murdered by her foster father- part 2.

Jason Brien.

Recap from part 1.           

     Tiahleigh Alyssa Rose Palmer was 12 years old when she was first placed in the care of the Thorburn family in Logan, QLD, Australia in January 2015. Before being placed with the Thornburns, Tiahleigh had been in and out of care homes and had been living with the Thornburn family for about 10 months before she was reported missing. Tiahleigh’s body was found on the banks of a Gold Coast river in 2015, 6 days after she was declared missing. Rick Thorburn murdered his foster daughter Tiahleigh to prevent anybody from discovering that his 18-year-old son Trent had been molesting the young school girl and he was fearful that she may have become pregnant as a result.

     The following is not directly related to Tiahleigh Palmer and the Thorburn family but describes how sibling incest may occur in situations like hers/theirs.  

     Sibling incest is notoriously taboo within society and laws exists to prevent its occurrence. Despite the name, sibling incest does not necessarily have to be between biological siblings. Some researchers suggest that sibling incest should be referred to as ‘psychological incest’ which better takes into account the violation of the sexual boundaries that exist within families especially amongst biologically unrelated siblings. Sibling incest most commonly occurs in larger families where there is an abundance of emotional and physical abuse, marital conflicts, blurred or non-existent intrafamilial boundaries and significant parentification. Parentification is where siblings take on parental roles to make up for the lack of parental leadership. Sibling incest can manifest when older siblings are responsible for showering or bathing younger siblings of either the same or opposite gender. Researchers have suggested however that within sibling incestuous relationships, the perpetrator is most always male and most always the oldest sibling and the victim most always female and most always one of the youngest siblings.  

     Unfortunately, due to the significant stigma associated with sibling incest and incest in general, it is often a neglected social issue with minimal resources allocated to deal with it and a profound lack of societal education. Most sibling incestuous relationships are only discovered at the time of pregnancy. Before then, the incest is hidden from schools, families, relatives, communities, professionals and even the parents. Many siblings who have been abused by an older sibling fail to report their abuse out of shame, guilt, fear, family loyalty etc. When the abused sibling does find the courage to speak up the abuse can be dismissed as “normal childhood experimentation gone a bit too far” which further demoralises and invalidates the sibling.  

     When parents or relatives discover the incestuous relationships, they are often ill prepared to deal with the seriousness effectively and will often continue to hide the abuse out of fear of social stigma further perpetuating and compounding the problem. The problem with keeping the incestuous relationship hidden and dealt within the family is that the perpetrator may be punished in ways which do not encourage reflection, insight, remorse or rehabilitation (i.e., getting severely beaten by either parent as opposed to criminal punishment and forced participation in sex offender rehabilitation programs for example) and the sibling that was abused may be unnecessarily punished and shamed for their unwilling role and thus denied the opportunity to resolve their abuse and trauma therapeutically. 


ABC News. (2018). Tiahleigh Palmer's foster father Rick Thorburn to plead guilty to murder. Retrieved from 

Ayling, L. (2020). Tiahleigh Palmer's evil foster father explodes in court as he's given MORE jail time for raping a little girl - five years after murdering his adopted daughter, 12, because his son, 18, was having sex with her. Retrieved from 

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