Sometimes searching in WISE isn't the fastest way to get where you need to be. If it suits your fancy, check out these:
Historical Abstracts Full Text
Also, it might be worth your time to search within The Journal of Genocide Research
If you don't know much about your topic, there's no need to jump into the primary literature right away. Instead, feel free to spend some time exploring library sources as well as the wider internet to get a sense of the conversation surrounding your topic.
Wikipedia: Fantastic for getting a sense of the main people, events, and issues surrounding your topic. So long as it doesn't wind up in your final product, read up to get a solid background.
Credo: A fancier wikipedia, Credo Reference has a great collection of reference resources surrounding your topic. Some entried even have great bibliographies to get you started
Googling: Just remember to keep that critical eye to web resources, especially with such important and emotionally charged topics.
Wise: Hey, I like it! Try typing your event into the search bar to the right to see what comes up