From Jessica Sachs’s “Expiration Date” (Legal Affairs: March/April 2004):
More than two centuries of earnest scientific research have tried to forge better clocks based on rigor, algor, and livor mortis – the progressive phenomena of postmortem muscle stiffening, body cooling, and blood pooling. But instead of honing time-of-death estimates, this research has revealed their vagaries. Two bodies that reached death within minutes of each other can, and frequently do, show marked differences in postmortem time markers. Even the method of testing eye potassium levels, which was recently hailed as the new benchmark for pinpointing time of death, has fallen into disrepute, following autopsies that showed occasional differences in levels in the left and right eye of the same cadaver. …
And the longer a body is dead, the harder it is to figure out when its owner died. In their book The Estimation of Time Since Death in the Early Postmortem Period, the world-renowned experts Claus Henssge and Bernard Knight warn pathologists to surrender any pretensions of doing science beyond the first 24 to 48 hours after death.