There may be a coronial inquest if nobody is indicted, and if so the findings will be published here:
http://www.courts.qld.gov.au/courts/coroners-court/findings
The coroner's finidngs would include a cause of death if it is possible to determine that. It will usually also refer to toxicology results if they are relevant to the cause of death. Coroners can no longer charge people with homicide in Qld but would refer the amtter to the DPP if a prosecution was not already on foot.
Reading coronial findings gives excellent insights into the nuts and bolts forsensic investigations and there are many published on that site.
If there is a trial then the best way to get an idea of the evidence is to attend it, assuming it's not just a guilty plea (which would be likely for manslaughter). It would be an open court and the prosecution would be likely to go through almost every piece of evidence they have.