From a law enforcement perspective, there are three supremely dangerous types of homicide: serial murders, spree killings, and acts of terrorism. Serial killers, especially those who are sociopaths, are able to easily hide in plain sight, sometimes for years on end. These killers are meticulous, difficult to apprehend, and their cases can go cold for years. These cases are not usually solved quickly, which drains resources from solving other crimes. Spree killings and acts of terrorism happen without warning and are very difficult to contain. These homicides cause widespread panic among the public which make enforcing the law significantly more difficult.
From a victim services provider perspective, the most dangerous homicides are those which cause the most mental damage to the victim. In some cases, this will include a homicide involving a close family member or friend of the victim. In other cases, it will include a homicide in which the victim feels like he or she could have stopped the crime.
From a prosecutor perspective, the most dangerous homicides are those which risk not returning a guilty verdict. These can be cases that have sensational media attention, such as the O.J. Simpson trial. These can also be cases which rely heavily on circumstantial evidence and/or unreliable witnesses. Losing a trial will impair the prosecutor’s ability to do his or her job in the future.