What is Lombard’s take on why these particular deaths brought everyone to the island?

. Lombard is sure that the Rogers were responsible for the death of their charge and Armstrong suggests that they might have killed the old woman by withholding a dose of amyl nitrate that would have been needed for a heart condition. In this way, there was “no positive action. No arsenic to obtain and administer – nothing definite – just – negation!” Lombard suggests that this explains Indian Island: all of these accusations are “crimes that cannot be brought home to their perpetrators.” As an example, Lombard tells Armstrong that he believes Wargrave murdered Mr. Seton. Armstrong thinks about his own accusation, and about how he thought he had been safe from retribution as well.