"If brutal killers like these two are at work, it is no wonder that so many people have fled," he said.

no 在这里表示否定，意思是"没有"。 wonder 的意思是"惊奇、惊讶"，也可以指"奇迹"。 no wonder 是一个固定短语，意思是"难怪、不足为奇"，表示对某种情况或结果不感到意外。