Philippine President Rodrigo Duterte’s eldest son quit as vice-mayor of the southern city of Davao on Monday, citing his link to a drug smuggling case by opponents and personal problems from a failed marriage as reasons for the move. Paolo Duterte and Manases Carpio, who is married to Mr Duterte’s daughter, Sara, are facing allegations that they helped facilitate a shipment of crystal methamphetamine worth $125.4m (£96m) into the country from China. President Duterte has said he would have his son killed if drug trafficking allegations against the younger politician were true, and that the police who carry out the hit would be protected from prosecution.