The authoritarian government of Venezuelan President Nicolás Maduro arrested a fourth American citizen, a top official said Tuesday, the latest in a string of foreigners detained in the government’s post-election crackdown. Venezuelan Interior Minister Diosdado Cabello, a hard-line Maduro ally, accused the U.S. national of a plot “against Venezuela” and said the fourth American had been detained in Caracas after allegedly taking photos of electrical, oil and military facilities. The American...