“I am still scared, because I don’t know what can happen,” Mr. Martyr said in a phone interview from Les Irois. “Even though he’s not in Haiti, he is still very powerful. He can call his supporters at any time and order them to kill anyone, even me. So as long as I don’t find justice, as long as this guy is not in jail, yes, I will be scared.”
Last month, Mr. Martyr and two other men filed the human rights lawsuit. But the next day, March 24, the case took another twist when Mr. Martyr suddenly became violently ill and died while watching a soccer match with his neighbors. He was 56 and had been in good health, his lawyers said. His lawyers are demanding an autopsy and a full investigation, but the authorities have not responded, and his body remains at the morgue.
Reached by telephone, Mr. Viliena said his lawyer had advised him not to comment.
Haiti has long been roiled by political turmoil. Government leaders ruled with the freedom to kill political opponents and silence dissent. The United States and other countries have poured millions of dollars into strengthening Haiti’s rule of law, but experts say it remains difficult to file criminal charges against people in power or their associates. The plaintiffs in the human rights case have already filed eight complaints with local and international agencies, the lawsuit says.
Haiti’s president, Jovenel Moïse, took office in February. He is the handpicked successor of the former president Michel Martelly, whose term was marred by a weak, corruptible judiciary and ties to human rights abusers, drug traffickers and kidnappers who avoided jail time. One of Mr. Martelly’s loyalists is Mr. Viliena.
When the country failed to hold elections for over a year, Mr. Martelly ruled the nation by decree with the power to appoint every officer-holder in the country. Among Mr. Martelly’s moves was to name Mr. Viliena, the former mayor, to be the top executive of Les Irois — even though by then he lived in Malden, Mass., and had an open murder charge against him.
“A common sentiment in Haiti is that justice is something for sale to the highest and most powerful bidder,” said Robert E. Maguire, a Georgetown University professor who has testified as an expert witness in other civil cases filed in American federal courts against Haitian officials. “The judiciary is weak and insecure, and usually subservient to the country’s president.”
To Mr. Martyr’s lawyers, the question is whether this history will repeat itself.
“With Martelly, it’s easy to say that there has been a pattern of impunity, not just with Viliena but with various officials accused of crimes or human rights abuses who have been treated as untouchable — that was the M.O.,” said Scott Gilmore, a lawyer at the Center for Justice and Accountability, which filed Mr. Martyr’s suit. “This case is going to represent a bit of a test case for them to see if they continue in that pattern Martelly followed or make a clean break.”
Neither the current nor former president responded to a request for comment.
The federal lawsuit is based on the 1991 Torture Victim Protection Act, which allows victims of human rights abuses overseas to seek compensation for their injuries from people who were acting in an official capacity. But the victims also want Mr. Viliena, who has said he is innocent, to be tried in Haiti on the charges involving the raid.
Other defendants, including Mr. Viliena’s father, have been convicted there on charges including murder and complicity in murder, but were released from prison early, Mr. Gilmore said .
“The irony is that extradition isn’t necessary, because he travels” back and forth to Haiti, Mr. Gilmore said. “They don’t need to extradite. They need to arrest him the next time he’s in the country.”
Mr. Viliena has demanded on Facebook that his associates be released from jail. “God saved my life, because there was a big plot manufactured against me,” he wrote in 2015, when his associates’ trial took place in Haiti.
Jean Richardson Philippe, a lawyer who represented Mr. Viliena in Haiti, said Haitian law allowed a judge to stay court proceedings and release suspects, as happened in Mr. Viliena’s case.
“There were no politics involved here,” Mr. Philippe said in a telephone interview. “Obviously he denied it. If he had admitted it, they would have locked him up.”
When the human rights lawsuit became public, Uber barred Mr. Viliena, and his bus driver’s license in the Boston suburbs was suspended.
The suit contends that the human rights violations were made possible because a power vacuum after a 2004 coup in Haiti gave rise to politically aligned militias. The one in Les Irois, where Mr. Martyr lived, became closely tied to Mr. Martelly, the former president. In another episode, the mayor is accused instructing associates to burn down the homes of his political opponents.
In 2007, a former Haitian Army colonel, Carl Dorelien, was sued in Florida under the Torture Victim Protection Act over the torture of a labor leader and the death of a man in a massacre in Raboteau, Haiti. Mr. Dorelien had won $3.2 million in the Florida lottery and was forced to pay his victims.
In 2006, the center won a case in New York against Emmanuel Constant, the leader of a paramilitary group who was accused of killing and torturing supporters of the former president Jean-Bertrand Aristide. He remains imprisoned on an unrelated matter.
In the lawsuit against Mr. Viliena, a victory would be largely symbolic, because an apparently unemployed school bus driver is unlikely to have many assets. If Mr. Viliena is not a United States citizen, he could be deported, as has occurred in other cases involving foreigners accused of atrocities. A spokeswoman for Immigration and Customs Enforcement said the agency could not speak about individual cases.
Nicole Phillips, a lawyer at the Institute for Justice and Democracy, a Boston-based group that helped prepare the lawsuit against Mr. Viliena, said the witnesses and plaintiffs were in peril.
“Their lives are still in danger,” Ms. Phillips said a few days before Mr. Martyr’s death. “None of them have slept through the night.”