“The Nazis had something called “Sippenhaft”, meaning family liability. So if you took a potshot at Hitler, your family was criminally punished along with you. It didn’t matter whether or not your family was actually involved.”
Under Stalin they were arrested as families of enemies of the people. The wives and children of his Party opponents became his hostages to make them confess, then were consigned to the Gulag anyway.
Molotov's wife was in prison for years.