ANTANANARIVO—Police in Madagascar this week arrested six people, including one foreign citizen, suspected of plotting to kill the president following what officials in the Indian Ocean island nation said was a months-long investigation. Madagascar has a history of political violence. Former coup leader Andry Rajoelina, 44, was sworn in as president in 2019 after a hard-fought election and a constitutional court challenge from his rival. “According to the evidence in our possession, these individuals had devised a plan for the elimination and neutralization of a number of people including the head of state,” the attorney general said in a statement. It added that investigations were still ongoing. The arrests were made on Tuesday. Officials did not give details on the extent of the plot or how far advanced it was when the suspects were apprehended. The attorney general’s statement did not specify the nationality of the foreign citizen allegedly involved. …