Thought I would share a resource to help with those considering motives and probable cause.
This url seems to provide a government statistical accounting of crimes. More specifically, this url addresses homicides.
Based on a "Victim Demographics" chart in the middle of the page I try to summarize in a few lines. On the right of the chart, I clicked on % to provide a clearer view of the population distributions.
1. Victim circumstances: About 50% of the time, the circumstances of the homicide do not have enough supporting data to specify.
2. Victim's relationship to the offender: About 52% of the time, the relationship is unknown.
3. Murder Victim's by instrument: Only 7% are with a knives or cutting instruments.
You may make your own conclusions.
Mine:
#3 narrows this type of homicide to 7%
of those it is more likely, the offender is not known and there is little evidence to determine who they might be.
Perhaps, you may add to this observation.