Christian Emmanuel Sanon, a Florida-based doctor, was arrested in Haiti.

The accusation that a Florida-based doctor was a central figure in the assassination of President Jovenel Moïse of Haiti has been met with bewilderment by some who knew him and surprise by prominent Haitian Americans who said he was not 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 Haiti’s presidency.

About two dozen people have been arrested in the killing, and 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 that he had not been in touch with him for a while and that 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.”

In a telephone interview on Monday, Michel Plancher, a civil engineering professor at Quisqueya University in Port-au-Prince, Haiti’s capital, 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 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.”

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 Haiti’s leaders as corrupt plunderers of its resources.

As the authorities focus on Dr. Sanon’s actions in recent months, a clearer picture of his past is 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 conventional medicine and 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 protection 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 had gotten 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.”

The empty streets of Port-au-Prince at dusk on Monday.
Credit…Federico Rios for The New York Times

Nearly a week after Haiti’s president was gunned down in his bedroom, the country is still wracked by questions over who was behind the killing, and their motives. And even as a state funeral is being planned for President Jovenel Moïse, political leaders are battling over who should lead the shaken nation.

Now, as a sprawling multinational investigation broadens, with suspects stretching from Colombia to Florida, the Haitian authorities have turned their focus to a little-known doctor who they said coveted the presidency. But how he might have managed to set in motion such an ambitious plot — involving perhaps two dozen heavily armed mercenaries recruited from abroad — is not easily explainable.

Our correspondent Catherine Porter, who has reported on Haiti during about 30 trips over many years, has now landed in Haiti. Here’s what she saw on her arrival.

PORT-AU-PRINCE, Haiti — Green mountains peek through the heavy clouds below me, little farms clinging to their steep edges seemingly by magic.

Haiti is a beautiful country.

Flying into Port-au-Prince Monday evening, I thought of a Creole proverb: “dèyè mòn, gen mòn.”

Mountains beyond mountains. It is used to portray the endless difficulties in life.

The Haitian eye doctor seated next to me on the plane explained one of the expression’s meanings: Nothing is simple. There are always many layers.

We agreed it seemed a perfect expression for Haiti, and this moment in particular.

A president assassinated in his fortified home. Not one of his bodyguards reportedly injured. A group of Colombian ex-military commandos labeled by the police chief as the culprits, and a Haitian-born American doctor the alleged mastermind.

Yet, if they were specially trained army commandos, why did they not have an escape plan? Why would they have announced their arrival via a loudspeaker, alerting the whole neighborhood, and not been covert?

The first time I came to Haiti was after another devastating event: the 2010 earthquake. I have returned some 30 times since to report, and on a few occasions to visit friends.

The first thing I noticed leaving the airport this time was how empty the city seemed. The normally bustling, chaotic streets were barren of life.

It became clear quickly that it wasn’t just from mourning.

As dusk fell, our car was enveloped in darkness as though we were in the countryside, not in a city jammed with more than one million people.

Few lights shone from the concrete two-story buildings around us: The city was experiencing another power outage — an increasingly common phenomenon that President Jovenel Moïse, killed on Wednesday, had promised and failed to fix.

When we did see people, they were lined up at a gas station, sitting in their cars and tap-taps — local buses made from converted pickup trucks. My fixer, Harold Isaac, explained that the city’s violently warring gangs had essentially shut down one of the country’s main highways, separating the city from its main gas reserves, causing fuel shortages.

Then we went through the Christ-Roi neighborhood, where 11 people, including a journalist and well-known activist, were gunned down on the street one week before the president.

Pink bougainvillea tumbled over the high walls lining the streets, like flowers atop gravestones.

There were many complicated problems in Haiti before Mr. Moise’s horrific assassination. His death has simply added to them.

Dèyè mòn, gen mòn.

The Haitian national flag was flown at half-mast at the former site of the Haitian presidential palace after the assassination of President Jovenel Moïse, in Port-au-Prince, on Saturday.
Credit…Ricardo Arduengo/Reuters

Haiti’s government has said it is setting up a committee to plan a state funeral for President Jovenel Moïse “with the respect, solemnity and dignity attached to his rank as head of state.”

Although no details were released about when the funeral will be held, information about the committee was published in Le Moniteur, Haiti’s official government journal, on Monday.

The committee includes the defense minister, the interior minister, the minister of foreign and religious affairs and the minister of culture and communication, in addition to the director general of Haiti’s National Pantheon Museum and two civil servants who work for the president’s office.

The government said on Twitter that it would hold a news conference on Tuesday at 11 a.m. local time to present the members of the committee.

Last Wednesday, just hours after Mr. Moïse was assassinated in his residence on the outskirts of Port-au-Prince, Le Moniteur published a government order declaring 15 days of national mourning.

The order called for the national flag to be flown at half-mast, nightclubs and other similar establishments to remain closed, and “invited” radio and television stations to program circumstantial programs and music.

Two days later, the interim prime minister, Claude Joseph, released a video on Twitter praising Mr. Moïse’s legacy.

“He believed in change that would last,” read one of the captions of the video, which showed images of Mr. Moïse mingling with crowds while a nostalgic piano soundtrack played in background.

“Rest in peace President,” Mr. Joseph wrote.

At the same time, Mr. Joseph declared a “state of siege” immediately after the assassination, effectively placing the country under martial law. In that period of 15 days, the police and members of the security forces can enter homes, control traffic and take special security measures and “all general measures that permit the arrest of the assassins.”

Mr. Moïse had planned to remove Mr. Joseph as prime minister, naming a replacement who was supposed to have been sworn in last week.

A group of the Colombian ex-soldiers at their compound in Haiti in the days before the assassination of the Haitian president.
Credit…Duberney Capador, via Yenny Carolina Capador

BOGOTÁ, Colombia — The retired soldiers trusted Duberney Capador because he was one of them: a former soldier who had spent years traversing Colombia, fighting left-wing guerrillas and other enemies in rugged conditions.

So when Mr. Capador, 40, reached out with a job offer — high-paying and important, he told them — many of the men jumped at the opportunity, and asked few questions.

The New York Times interviewed a dozen retired Colombian soldiers who were recruited for a potentially dangerous security operation in Haiti shortly before the president’s assassination last week. The soldiers interviewed did not end up participating — in some cases because they were part of a second wave of people who were supposed to arrive in Haiti at a later point, they said.

The exact relationship between Mr. Capador, the ex-soldiers and the death of the president is unclear. But Mr. Capador died in the aftermath of the assassination, and Haitian officials have 18 Colombians in custody in connection with the president’s death.

The narrative began with Mr. Capador, who retired from the military in 2019 and was living on a family farm in western Colombia with his mother. His sister, Yenny Carolina Capador, 37, said in an interview in Bogotá that Mr. Capador had received a phone call in April from a security company that asked him to put together a group that would “protect important people in Haiti.”

Mr. Capador took the job, and by mid-May he had flown with a military buddy to Haiti to find a home base for the men and gather supplies.

He also started recruiting his military friends and asking them to call their friends. He organized them in at least two WhatsApp groups, and told them to buy boots and black polo shirts and to prepare their passports.

Some of the men said they had been promised $2,700 a month.

Carlos Cifuentes, one of the men recruited by Mr. Capador, said he had been told that it would be a “long-term post, initially a year.” Mr. Cifuentes said he had been told he would be fighting drug trafficking and terrorism.

Others were told that they would be providing security for “dignitaries” and “important people.”

“All we know is that we were going to provide security in an exclusive area under the command of Mr. Capador,” said one recruit who asked that he not be named to protect his safety. “We weren’t interested in how long, or where, or the name of the person we were going to protect. For these types of jobs there are never any details.”

Two of the 12 people interviewed said they had been told they would be protecting a president.

Others said that they had struggled to find well-paid work after leaving the military.

“I’ve been out of the military for four years and I’ve looked for work,” said Leodan Bolaños, 45, one of the recruits. What he had found paid too little, he said.

Mr. Capador started one of the WhatsApp groups, called “First Flight,” on May 26. By early June, the first wave of men had arrived in Haiti, several of the ex-soldiers said.

“We’re doing well,” wrote a former soldier in Haiti to one of the recruits still in Colombia, “they’re treating us like they promised.”

But the second wave of men never arrived.

Haitian officials say that a group of assailants stormed President Jovenel Moïse’s residence on the outskirts of the capital, Port-au-Prince, last Wednesday at about 1 a.m., shooting him and wounding his wife, Martine Moïse, in what the Haitian authorities called a well-planned operation that included “foreigners” who spoke Spanish.

On Monday, the head of Colombia’s national police, Jorge Luis Vargas, said Colombian officials had determined that at least two of the Colombian ex-soldiers found in Haiti, including Mr. Capador, had contact with a Florida-based company called CTU Security, run by a Venezuelan American named Antonio Intriago. But Mr. Vargas said nothing about Mr. Capador’s motives or the motives of the many men who followed him to Haiti.

Edinson Bolaños and Sofía Villamil contributed reporting.

A mural of the assassinated President Jovenel Moïse near his house in Port-au-Prince, Haiti.
Credit…Orlando Barria/EPA, via Shutterstock

The photos are horrifying. They seem to portray the body of President Jovenel Moïse of Haiti laid out in the morgue, his left eye crushed in, the flesh of one of his arms torn by bullets, his mouth gaping.

A country already reeling from the assassination of its leader on Wednesday and the chaos that followed reacted to the images with horror and despair, afraid that the photos circulating on social media channels would rip the last shreds of dignity from both the person and the office he held.

Even his critics were outraged.

“Even if @moisejovenel was decried and declared a de facto president, let’s not go down to the level of dehumanization established by the @PHTKhaiti,” tweeted the journalist Nancy Roc, referring to Mr. Moïse’s political party. “Haitians are better than that.”

She was among many who beseeched others not to forward the photos that were circulating through the country’s buzzing WhatsApp channels.

The authenticity of the pictures could not be independently confirmed, but Mathias Pierre, Haiti’s minister in charge of elections, told the Nouvelliste newspaper that an autopsy had been carried out on Mr. Moïse’s body. He also seemed to suggest that the photos circulating online had come from that autopsy.

“The corpse was taken to a center for a CT scan. That’s where the pictures were taken,” Mr. Pierre said.

Forensic experts consulted by The Times who reviewed the photographs said that rumors that Mr. Moïse had been tortured — which swirled around social media along with the photos — were unlikely to be true.

“I don’t see anything that looks like it would be typical of torture,” said Dr. Michael Freeman, an associate professor of forensic medicine at Maastricht University in the Netherlands. Dr. Freeman noted that an autopsy would be needed to determine conclusively whether Mr. Moïse was tortured, but the wounds visible in the photographs appeared consistent with gunshots.

“The fact that he’s not bound is a pretty strong indication that he’s not been tortured,” Dr. Freeman added.

Photos of dead bodies left on the streets are sadly regular fare in Haiti. But that the country’s leader would face the same wretched indignity seemed to underscore just how cheap life had become in the country.

The Rev. Rick Frechette, an American Catholic priest with the Congregation of the Passion order and a doctor who regularly treats Haiti’s poor in clinics in Port-au-Prince’s slums and in the hospitals he built in a suburb of the capital, said that for some of his staff members, the president’s brutal assassination had brought back memories of past violence.

“People are traumatized and afraid,” he said.

And then there were those who believed the distribution of the photos was politically motivated, part of the struggle over who will govern the country in the president’s absence.

“Last night’s photos show how much they want to create a climate of violence and instability in the country after their heinous crime,” tweeted Danta Bien-Aimé, a nurse and former Fulbright scholar.

Harold Isaac contributed reporting from Port-au-Prince, Haiti.