Haitian officials investigating President Jovenel Moïse’s assassination arrested the head of palace security Thursday, the investigation’s first step in looking inward. Dimitri Hérard, the palace’s security chief, was arrested after he and three other Haitian security officials spoke with investigators Wednesday, The New York Times reports. According to the Times, Hérard had made several stops in Colombia in recent months, the home of more than 20 people suspected to be involved in Moïse’s death. None of Hérard’s security officials fired their gun when about 25 individuals broke into the presidential palace and assassinated Moïse. Haitian police said two other people in the country were arrested Wednesday night, where they were found harboring weapons. It comes as the U.S. said about six of the Colombians involved had received training from U.S. military soldiers.