On television, you have probably seen homicide detectives working cases. What some people might not realize is that the term "homicide" doesn't automatically mean that there was an illegal action involved in the case. In the simplest of terms, a homicide is any unnatural death of an individual. This can be because of an illegal action by someone, such as murder, but it can also be due to an accident, such as a fatal car wreck.
The purpose of the homicide detective is to determine what happened so they can figure out what to do about the death. It is fully possible that no criminal charges will be filed even though the homicide team is called in to check out the situation.