The president of the Samarco mining company and six other people have been charged with aggravated homicide over the deaths of at least 17 people after a dam burst in November, the Brazilian police said Tuesday. The police in the state of Minas Gerais said they had requested that Samarco’s president, Ricardo Vescovi, five other company executives and one contractor be held in preventive detention while awaiting trial. The men are charged with homicide, causing a flood and polluting drinking water. A wave of debris from an iron-ore mine broke through the Fundão dam on Nov. 5.