There is a general acceptance that giving the exact time or even hour of death is more of a public misconception. In truth there is usually a margin of error and so the forensic pathologist will generally give an interval of time that is most likely.
Through the ingenious use of such sites as body farms, researchers can assess the environmental factors which can affect time of death such as heat, cold and insect activity. On the third factor, it's well known that entomological (Insect activity) consideration can help in some instances of narrowing down the timeline of dumped body.
Various lifecycle stages of different insects such as flies are well known and this is a source ofinvaulabel information. I would recommend the book 'Stiff: The curious lives of Human Cadavers' by Mary Roach for more info on body farms etc.
Modern pathological research reveals that instead of relying onone measure such as heat, a nearer approximation to TOD (Time of Death) can be gained by employing multiple methods.
@Daniel Sumner I didn't know about presence of insects can also determine time of death. Where can I find the book you mentioned in your answer?
@ayesha naymat Yeah so using insect activity is called forensic entomology and it's a fascinating field.
The book can be found on Amazon and other places. More info can be found here:
@Daniel Sumner Thank you! For letting me know about the book. forensic etymology fascinates me after reading your post.
Rigor mortis and measuring core body temperature forensic scientists determine time of death.