Subject: can excess potassium befound in the blood on autopsy that suggests homicide

Injection of an adequate dose of potassium chloride intravenously will cause 
arrhythmia and cardiac arrest in a human due to distruption of action potential 
across the heart muscle cell membrane. This is a well known fact and has been 
employed in novels and movies from time to time in the past (eg House of God by 
S. Shem) as a reliable means of murdering someone. Apparently, the beauty of 
this was that the mechanism of death would not be easily detected, since - 
following death - serum potassium levels increase as cells begin to lyse in a 
corpse. 

My question is one to the pathologist: is there technology in necropsy now 
available which can detect whether someone has died due to a potassium 
injection? If so, what kind of methodology is used, including equipment? Also, 
what would make a pathologist suspicious of this if a medical history is 
inconclusive?

(no, i'm not a raving murderer - i'm writing a novel with this in mind)

Regards

Re: can excess potassium befound in the blood on autopsy that suggests homicide