He claims that Speck "bound them [the nurses] and held them at gunpoint. When some of them resisted, he killed all eight that he could find" (48).

In point of fact, the nurses DIDN'T resist Speck. The American nurses convinced the Filipina nurses not to. After he'd tied them up, he took them out of the room one by one and raped them before killing them.

So Speck's motivation for murder is not what Stone says it is. And forgetting the rape part of the rape and murder of eight nurses makes me doubt his mastery of his material.