Jovenel Moise was shot dead when assassins armed with assault rifles stormed his home in the hills above Port-au-Prince, tipping the country into uncertainty and sparking a frenzied investigation to identify the authors of the plan.
The Prime Minister's office tweeted a video of Martine Moise arriving back at the Haitian capital's Toussaint Louverture international airport on Saturday, wearing all black clothing, donning a bullet proof vest and with her right arm in a sling. She was greeted by Interim Prime Minister Claude Joseph.
"The Prime Minister, Dr. Claude Joseph, welcomes the First Lady, Martine Moise, who arrives in Haiti for the funeral of her husband," the Prime Minister's office said.
Martine Moise had tweeted earlier this week while in Miami that she was still coming to terms with the killing of her husband and had thanked a "team of guardian angels who helped me through this terrible time."
Earlier on Saturday, the important Core Group of international ambassadors and representatives had urged "the formation of a consensual and inclusive government".
"To this end, we strongly encourage the designated Prime Minister Ariel Henry to continue the mission entrusted to him to form such a government," the group said. Henry, who Moise designated Prime Minister shortly before being killed, has not been sworn into his position and the country is being led by Joseph.
The Core Group is made up of ambassadors from Germany, Brazil, Canada, Spain, the United States, France, the European Union and special representatives from the United Nations and the Organization of American States.
"As Haiti faces serious dangers, the members of the group express the wish that all political, economic and civil society actors in the country fully support the authorities in their efforts to restore security throughout the country," it said.
The group also called for the organization of "free, fair, transparent and credible legislative and presidential elections as quickly as possible".
Senior opposition Senator Patrice Dumont, one of only 10 sitting lawmakers in the normally 30-seat Senate said on Thursday that fair elections cannot be held for at least a year due to the influence of violent gangs and a compromised electoral council.
On Friday a Colombian police chief said the assassination may have ordered by a former Haitian justice ministry official, citing a preliminary investigation that has implicated Haitian-Americans and former Colombian soldiers.