People lay carnations on a memorial for Yevgeny Prigozhin, who died in a plane crash, near the PMC Wagner Center in St. Petersburg, Russia, on Aug. 24, 2023. Anadolu Agency via Getty Images For two months after Yevgeny Prigozhin led a brief mutiny that threatened Russian President Vladimir Putin’s hold on power, the mercenary boss traveled freely, attending to business in St. Petersburg and Moscow, as if all were forgotten and forgiven. But on Wednesday, a very suspicious plane crash killed Prigozhin and decapitated his Wagner Group, the mercenary army that marched on Moscow in June under his command. Dmitry...