Research: Post Mortem Bruise

Here is what I'm researching this week:

Post Mortem Bruises -- A possible line of defence for a person charged with homicide could be that the bruises were not in fact made during life, but are post-mortem artifacts.

However, it is very difficult to produce a bruise in a dead person, because it is very much a 'vital reaction' to injury. It may be possible to produce a bruise following very severe trauma in an area of post-mortem lividity (where blood has drained to dependant parts of the body under the influence of gravity), and if there is any doubt the pathologist should examine the 'bruise' histologically. However, in the absence of an organising haematoma, histology may only show the presence of haemosiderin, and even then only after approximately 48 hours. (source)

For an example of post-mortem bruising, see CSI:Las Vegas, "Happenstance."