Psychological Profile
 
After a careful review of the violent and powerful nature of these murders, I believe the killer to be a male, twenty-five to thirty-five years of age, with above average intelligence.
 
His manner of entry has so far been undetectable.  This may be due to his superior knowledge of the inner structure of buildings and duct work, or that he in fact hides in plain sight, posing as delivery or maintenance workers. Witnesses tend to overlook such personnel, their uniform rendering them invisible to casual observers.
 
The extraction of the liver is the most significant detail of these crimes. The liver possesses regenerative qualities.  It cleanses the blood.  The taking of this "trophy" is the transferring act for the killer to "cleanse" himself of his own impurities.  I think he is acting under the classic form of obsessive-compulsive behavior.
 
Since the victims are unrelated, and we cannot predict who will be next, we must utilize the fact that a killer will not always succeed in finding a victim.  When this occurs, the serial killer may return in frustration to the sight of a previous murder, hoping to recapture the emotional high.  I think our best course of action is to target these sites.