Yes. However, the other side of that problem is that multiple murders come in different forms.
The other form of multiple murder involves separate incidents in which a person has killed twice. These are single incidents involving a single police force, usually in a single location, and there are two or more victims. If a person kills somebody on this side of town and then kills another person tomorrow on another side of town, those are going to be deemed as two separate incidents, even though you and I would say that the person has killed two people.