vinegarteeth:

Just so everyone is perfectly clear:

• serial killer = killed three or more people, all at separate events/times
• mass murderer = killed a large number of people (usually 4+) in one event
• spree killer = killed two or more people in a short time at multiple locations

Because not everybody knows the actual definitions of these terms, and at times I see people misusing them, and I just want the proper information to be known.