A lengthy investigation led to the decision to throw out the 1966 convictions.
So far, more than 40 suspects have been detained in connection to Moïse's death, but police have not yet determined a motive.
"Threats should be taken seriously and our laws should be enforced to ensure accountability," a spokesperson for the Republican senator said.
Prime Minister Ariel Henry dismissed two government officials this week for seeking to interview him regarding President Jovenel Moïse's assassination.
"There are enough compromising elements ... to prosecute [Prime Minister Ariel] Henry and ask for his outright indictment," prosecutor Ben-Ford Claude wrote in the order.
"Our family and our country suffered an unspeakable loss due to the inhumanity of one man," Ethel Kennedy said.
Joseph P. Kennedy II said Sunday that anyone who kills for political reasons should "know that he will at a minimum spend life in prison without parole. "
Majority of slain presidential candidate's nine surviving children said they were "devastated" by the decision as two had pushed for his killer to be freed.
Sirhan Sirhan has claimed to have no memory of the shooting, only the events before and after.
The president of Worldwide Capital Lending Group is under scrutiny for his alleged role in funding the operation as the investigation continues.
Jimmy Cherizier, a former police officer and leader of the nine gang coalition "G9" spoke to an assembled crowd demanding justice for Moise's death.
In the clip, the man—along with others—fires his gun at various targets as he maneuvers behind different barricades to shield himself.
Andry Rajoelina first seized power in the Indian Ocean island nation in a 2009 coup. In 2018, he won the presidential election with 55 percent of the vote.
The attempt on the president's life comes amid several jihadist attack in Central Mali in recent days.
In one neighborhood, residents tied suspects' arms with rope and forced them to walk while yelling "Move! Move!" until they could hand them over to police.
Officials say the proof was a photo they found in which men working for the firm were meeting with Colombian Americans suspected of being involved in the assassination.
A report from a Columbian-based private TV station claimed government officials were involved in the assassination of President Jovenel Moïse.
"This villainous act is an affront to our democracy," the Haitian government's anti-corruption unit said.
Authorities have detained 18 of the Colombians, in addition to three Haitians also suspected in the killing.
"Tears will never dry from my eyes. My heart will always continue bleeding. But we can't let the president die a second time," Haiti's first lady Martine Moïse said.
"We are going to bring them to justice," National Police Chief Léon Charles said, as the 17 handcuffed suspects sat on the floor.
Joseph Vincent, 55, and James Solages, 35, were reportedly detained following Wednesday's assassination of Haitian President Jovenel Moïse.
Six people have been arrested in connection to Haitian President Jovenel Moïse's assassination, including two people believed to be Haitian Americans.
Claude Joseph has been leading the country, but he was supposed to be replaced by Ariel Henry, whom Moïse named prime minister a day before his death.
Haiti's National Police say that officers remain "engaged in a battle" with additional armed suspects.
"If Haiti just quietly sunk into the Caribbean or just rose up 300 feet, it wouldn't matter a whole lot to our interests," then-Senator Biden said in 1994.
Arrangements have been made for her to be taken to Baptist hospital for treatment. Officials say her vitals are stable but critical.
"The situation is dire. We're praying for peace in Haiti," Pastor Dieufort Fleurissaint said after Haitian President Jovenel Moïse was shot and killed.
The international airport in Haiti was closed as the country declared a "state of siege" following Moise's assassination early Wednesday.
World leaders are reacting to the assassination of Jovenel Moïse, 53, during an attack on his private residence.