When the cause of death is undetermined, this can mean quite a few things. At first glance it appears that the medical examiner simply cannot conclude how the person died; however, it is not quite that simple. The main problem is that “undetermined” doesn't just mean figuring out how a person died, it's also about understanding intent. Despite substantial evidence, if a medical examiner cannot reconcile her findings with the intent surrounding the death, she will often list the cause of death as undetermined in accordance with legal standards.
TL;DR (Too Long; Didn't Read)
A medical examiner may list the cause of death as "undetermined" when she can't figure out the manner of death or the intent behind why the person died.
Meaning of "Undetermined"
Most states recognize five causes of death: undetermined, natural, homicide, suicide and accidental. Homicide, suicide and accidental all involve understanding the intent behind the death. A medical examiner may classify the cause of death as undetermined if he doesn't understand intent at the conclusion of an autopsy; if he cannot say for sure what caused the death. For example, if a person with severe heart problems dies of a heart attack and is found to have a large dose of cocaine in his system, it may not be clear if the heart attack was natural or caused by the cocaine. If the medical examiner cannot conclude, he might list the death as undetermined.
Problems in Possible Homicide
In order to list a cause of death as homicide, the medical examiner must conclude from the autopsy that the death resulted from a violent act where a human being was responsible for the death. If the autopsy does not reveal sufficient evidence that the death resulted from homicide, even if there is evidence of possible homicide, this may result in an "undetermined" ruling. In other cases, it might be just the opposite. If a person receives a gunshot to the head, for example, the medical examiner may conclude a person died of homicide although it may very well been the result of an accident.
Problems in Possible Suicide Cases
The medical examiner must conclude beyond a reasonable doubt that the person intentionally meant to kill himself. This can prove tricky for a medical examiner, because once again he does not know the intent if there are not other reports available to help him make that determination. If a person dies after drinking a large amount of alcohol and ingesting a large number of sleeping pills, it might appear as suicide, but there is reasonable doubt. The person might not have realized how many pills he was taking or meant to take something else, not sleeping pills. Many suicides end up as undetermined classification due to the lack of knowledge surrounding intent.
Problems in Possible Accidental Cases
Accidental cases present the exact same issues. Intent makes a big difference between homicide, suicide and an accident. Since a medical examiner knows nothing of intent, if the autopsy does not conclusively tell him that a death was the result of an accident, he is still reluctant to call it homicide of suicide, resulting in an undetermined classification. An accidental death is a death that occurs in an unintended manner. This can be hard to tell in an ongoing investigation.