LindaL100 you didn't link to your source material so I was unable to read your references but I did find this:
After perusing this article I would say the above definition does suit Ollie.The different discussion groups at the Symposium agreed on a number of similar factors to be included in a definition. These included:
• one or more offenders
• two or more murdered victims
• incidents should be occurring in separate events, at different times
• the time period between murders separates serial murder from mass murder
In combining the various ideas put forth at the Symposium, the following definition was crafted:
Serial Murder: The unlawful killing of two or more victims by the same offender(s), in separate events.