"All states have an obligation to prevent crimes against humanity," he said. "[But] dictators would find it uncomfortable to come to us, because we allow class actions suits...for individuals whose rights were violated."
Pinochet was not in London for official business but, instead, to undergo surgery.
"Official business is really the key to the diplomatic immunity argument," Myers said, explaining why the immunity might not protect Pinochet.
But Spain also has a particular interest, Myers said, in investigating the alleged murder of 30 to 40 Spaniards by Chilean security forces during Pinchot's years as head of state.
Myers said he reacted with surprise and satisfaction to the news of Pinochet's arrest last week.
While his work in this case is far from complete, Myers predicted that it will have a prominent position in international legal history.
"This precedent shows that the international community is no longer willing to overlook human rights violations simply because the people who committed them continue to have influence in their home countries," Myers said.