assassination of President Jovenel Moïse of Haiti was met on Monday with bewilderment by some who knew him and surprise by prominent Haitian Americans who said he had not been known as a major political player.
At the same time, a university professor who met with the doctor twice last month said that he had spoken then of being sent by God to take over the Haitian presidency.
Some two dozen people have been arrested in the killing, but Haitian officials have placed the doctor, Christian Emmanuel Sanon, 63, at the center of an investigation that has stretched out from Haiti to Colombia and the United States.
The doctor’s brother, Joseph Sanon, said he had not been in touch with him for a while and he had no idea what was going on. “I am desperate to know what’s happening,” he said.
A former neighbor of the doctor’s in Florida, Steven Bross, 65, said, “He was always trying to figure out ways to make Haiti more self-sufficient, but assassinating the president, no way.”
But in a telephone interview on Monday, Michel Plancher, a civil engineering professor at Quisqueya University in Port-au-Prince, said he had received a call from out of the blue to attend a meeting with Dr. Sanon, who he was told was planning a political campaign.
Professor Plancher said he had never heard of the doctor but decided to attend the meetings, which were held at a home in the capital, after internet searches showed Dr. Sanon to be a pastor who had done charitable work.
The two men had a first meet-and-greet encounter on June 1, Professor Plancher said. The initial contact was followed a day or two later by an hourlong meeting with Dr. Sanon and a group of six to eight people. Both meetings happened in the same home in the capital, Port-au-Prince.
There, he said, Dr. Sanon outlined his political ambitions.
“He said he was sent by God. He was sent on a mission of God to replace Moïse,” Professor Plancher said. “He said the president would be resigning soon. He didn’t say why.”
“He said he will implement a Marshall Plan to run the country,” Professor Plancher added. “He wanted to change French as an official language, and replace it with English. He seemed a bit crazy. I didn’t want to participate anymore.”
Haiti’s national police chief, Léon Charles, has accused Dr. Sanon of playing a pivotal role in the assassination and wanting to become president, but offered no explanation for how the doctor could possibly have taken control of the government.
During a raid of his home, the Haitian authorities said, the police found a D.E.A. cap — the team of hit men who assaulted Mr. Moïse’s home appear to have falsely identified themselves as Drug Enforcement Administration agents — six holsters, about 20 boxes of bullets, 24 unused shooting targets, and four license plates from the Dominican Republic.
A YouTube video recorded in 2011 titled “Dr. Christian Sanon — Leadership for Haiti” appears to present Mr. Sanon as a potential leader of the country. In it, the speaker denounces the leaders of Haiti as corrupt plunderers of its resources.
As the authorities focused on Monday on Dr. Sanon’s actions in recent months, a clearer picture of his past was also coming into view.
Dr. Sanon was born in 1958 in Marigot, a city on Haiti’s southern coast, and graduated from the Eugenio María de Hostos University in the Dominican Republic and the Midwestern Baptist Theological Seminary in Kansas City, Mo., according to a short biography from the Florida Baptist Historical Society.
Public records show that Dr. Sanon was licensed to practice both conventional medicine as well osteopathic medicine, in which doctors can provide therapies like spinal manipulation or massage as part of their treatment.
In 2013, he filed for Chapter 7 bankruptcy in Florida, a process in which people can liquidate assets to pay creditors. Dr. Sanon stated at the time of his bankruptcy filing that he was a doctor and the director of the Rome Foundation, a nonprofit involved in assisting people in Haiti.
Dr. Ludner Confident, a Haitian-born anesthesiologist who practices medicine in Florida, said he got to know Dr. Sanon while they were working for the foundation in the years before the devastating 2010 earthquake.
“He is a pastor,” Dr. Confident said. “He’s a man of God, wanting to do things for Haiti.”
Still, Dr. Confident, who said he had not spoken with Dr. Sanon for years, said, “When it comes to politics, I don’t have any information about his political agenda.”
And though Dr. Sanon was straddling two worlds, dividing time between his homes in Haiti and Florida, some in Miami’s Haitian diaspora expressed surprise when Dr. Sanon was named as a central figure in the assassination plotting.
“I never heard of this Sanon before,” said Georges Sami Saati, 68, a Haitian American businessman who is a prominent figure in Miami’s community of Haitian émigrés. “Nobody ever heard of him.”