Homicide by Unspecified Means

Let’s imagine you are a forensic pathologist, called by investigators to the basement of an abandoned house where a building inspector found human remains. Upon your arrival, you identify a human skeleton, still partially encased in trash bags. The plastic trash bags have melted over the exposed surfaces, and there are charred cans of lighter fluid lying on top of the body. After a full examination of the body at your morgue, however, you cannot find any remaining signs of injury. One need not be an expert to recognize that the circumstances in which this body was found are extremely concerning, regardless of the absence of injuries at autopsy. This is when the diagnosis of “homicide by unspecified means” (“HUM”) enters consideration.

As we have previously discussed (see Undetermined, Undetermined – Lablogatory), in situations of extensive soft tissue loss or incomplete remains, we may not be able to identify the cause of death. It is unfortunately not uncommon for bodies of homicide victims to be concealed, delaying their discovery and allowing decomposition to progress. Out of a desire to hide the victim’s identity or to conceal the crime itself, attempts may be made at dismembering or destroying the body, which can further hinder efforts to identify injuries. Still, there are situations which are easily recognized as suspicious – yet we need to be careful to not rush to conclusions. There are less malignant explanations for some strange circumstances – for example, a person who accidentally overdoses may be moved to a different location, to divert law enforcement attention from a specific house or person. A hiker in an isolated location may suffer a natural cardiac event but not be found before decomposition and animal predation have occurred.

There are five criteria required to meet the diagnosis of “homicide by unspecified means,” a term which was originally coined by the late Dr. Joe Davis in Miami, Florida. These criteria were designed to ensure that all possible alternatives are thoroughly considered before arriving at the diagnosis. The criteria, as delineated in the original 2010 article, are:

Objectively suspicious circumstances of death. This would include evidence that the body was deliberately concealed (in trash bags, luggage, or a shallow grave, for example), attempts were made to destroy the body (e.g. with fire, or bleach), or that the victim was restrained. There may be evidence at the scene (or in the victim’s home) of significant blood loss, or there may still be non-lethal injuries (for example, a shallow laceration, or numerous bruises) identifiable on the body.
No anatomic cause of death. Meeting this criterion requires the completion of a full autopsy, despite the potential lack of tissue or complete remains. Sometimes evidence of lethal trauma is still identifiable – for example, gunshot wounds or knife marks on bone – and in this situation, the better “cause of death” is the specific type of injury. In other situations, there may be significant cardiovascular disease found at autopsy; the presence of a competing, natural cause of death must be carefully weighed with the other evidence.
No toxicological cause of death. This essentially means we have excluded an overdose as a possible cause of death. At times, this is a difficult standard to meet – in the example of skeletal remains, no material may be present to test. Other remains may be so decomposed that obtaining quantitative results (rather than qualitative) is impossible. Even if results are ‘positive’ for drugs of abuse, there is strong evidence that intoxicated individuals are at increased risk for interpersonal violence, and it would be a public disservice to automatically ascribe these deaths to overdose. This criteria, much like criteria #2, needs to be considered carefully in the context of all other findings.
No environmental, circumstantial, or historical causes of death. One always needs to consider the scene investigation and surrounding environment. Take the example above of a hiker in an isolated location – a death from hypothermia can have no or minimal findings at autopsy, let alone in the context of decomposition. Deaths due to drowning, epileptic seizures, or transient exposure to a toxic agent (like carbon monoxide) are similarly difficult to identify in these circumstances. If any of these possibilities cannot be confidently excluded, the diagnosis of “HUM” should not be made.
A more specific cause of death cannot be suggested by the data set. Essentially a reminder to review the totality of the evidence. Ruling a death as a ‘homicide’ sets off a chain of events which could result in a person being permanently incarcerated or executed. It is not a ruling to be made lightly.

Not every jurisdiction uses “HUM” as a term. Some will rule the cause of death as purely ‘undetermined’ and the manner of death ‘homicide’. In either case, the point is the same – there are clear indicators of homicidal violence, yet we cannot determine the specific type – and these criteria are still helpful to make sure alternative manners of death are thoroughly considered.

References:

Matshes EW, Lew EO. Homicide by unspecified means. Am J Forensic Med Pathol. 2010 Jun;31(2):174-7. doi: 10.1097/PAF.0b013e3181df62da. PMID: 20436340.

Krywanczyk A, Gilson T. Homicide by Unspecified Means: Cleveland 2008 to 2019. Am J Forensic Med Pathol. 2021 Sep 1;42(3):211-215. doi: 10.1097/PAF.0000000000000657. PMID: 33491950.