Thanks very much to everyone for the exceedingly warm welcome
Just some information regarding the discovery of Allison's body and the evidence that lead forensics/police to determine that Allison was deceased before her body was dumped. I apologise for the length of this post and doubly so if there are any members who are disturbed or upset by any of the subject matter.
When a human body has been discovered and the crime scene properly secured, the police will then work in conjunction with active investigating personnel to gather evidence and to attempt to pinpoint a cause of death. It is generally the police on scene who will initially note the position of the body and to record any obvious injuries or possible cause/s of death. The police will also note the physical conditions of the crime scene and any obvious evidence such a footprints, vehicle impressions, weapons, etc.
The forensics team on site will generally consist of one or two death investigators, a forensic photographer and any other experts that police feel might be able to assist with the investigation such as a ballistics expert or an expert in detecting trace elements and blood patterns. They will then work with police (generally, at this point, with assigned homicide detectives) to establish whether the death took place at the crime scene, whether there have been any attempts to tamper with or alter the crime scene, if the crime scene suggests correlating factors such as burglary or drug abuse, if the cause of death is obvious and if there are clues to suggest how the death occurred.
It is reasonable to assume that police and other personnel established at a fairly early point that the location of Allison's body was not the actual scene of her death. Circumstances that lead them to that opinion were possibly based on a number of factors, most notably the condition of her body, the fact that the area had been subjected to heavy rain and it was very likely that her body had travelled some distance, whether great or small, the position of her body and the lack of physical or forensic evidence at the scene.
It is my belief that the condition of Allison's body was more than likely a major factor in establishing that she was not killed where she was found and that she was dumped under the bridge after death.
As in Allison's case where no visible signs of foul play were perhaps immediately evident, a forensic entomologist is then employed to establish whether or not drowning was the official cause of death and when the approximate time of death occurred. Once drowning has been ruled out, the body is examined for other evidence of foul play and for the presence of pupae and other insects. These pupae are crucial in determining an approximate time or date of death and their presence can tell a forensic entomologist a lot about where the body has been. Blood pooling under the surface of the skin and rigor mortis would also have been taken into account to establish time of death.
Determining whether injuries suffered to the body occurred post or ante mortem is usually left to the coroner, but it should be noted that a body will decompose at a much slower rate in running water than it will in stagnant water, and obviously in cold water as opposed to warm. That said, lividity is most common in the head, neck and chest areas where victims have been submerged in water after death and then re-surfaced. This can make it very difficult to determine an "obvious" cause of death simply by looking at the body, particularly in cases where strangulation has been the cause of death.
Based on the process that is followed to determine a cause of death, the police are more than likely keeping whatever evidence they discovered out of the public eye at this point in their investigation. It is almost impossible to logically accept that there were no visible or obvious signs of foul play present on Allison's body at the time she was discovered, especially given that police released a statement saying that they were confident that they knew how she was killed.
It all adds to the mystery of her disappearance and death, but I have every confidence that the QPS are doing everything they can do gather all the evidence they need to make an arrest. I hope some of this information has been useful or at least shed some light on the processes involved in determining cause and time of death.
