Haitian officials say Samir Handal is a suspect in the killing, but have not given details of his alleged involvement.
Two of the 17 Christian missionaries kidnapped in Haiti last month have been released, according to the group’s United States-based church organisation.
In a statement on Sunday, the Christian Aid Ministries said, “We have learned that two of the hostages in Haiti were released.”
It said it could not give the names of those released, why they were freed or other information.
“While we rejoice at this release, our hearts are with the 15 people who are still being held,” it added.
The 16 Americans and one Canadian, including five children, were abducted in October after visiting an orphanage. Their Haitian driver was also taken hostage.
The leader of the gang that kidnapped the group has threatened to kill the hostages unless his demands are met. Authorities have said the gang, known as the 400 Mawozo, was demanding $1m per person, although it was not immediately clear if that included the children in the group.
Gary Desrosiers, spokesman for the Haitian National Police, confirmed that two hostages had been released on Sunday.
The FBI, which is helping Haitian authorities recover the captives, declined to comment.
The release comes as Haiti struggles with a spike in gang-related violence and kidnappings, with the US government recently urging Americans to leave Haiti amid deepening insecurity and a severe lack of fuel blamed on gangs blocking gas distribution terminals.
On Friday, Canada announced it was pulling all but essential personnel from its embassy.
The fuel shortage has forced hospitals to turn away patients and paralysed public transportation, with some schools closing and businesses shortening their work hours.
Haiti also is trying to recover from the July 7 assassination of President Jovenel Moise and a 7.2 magnitude earthquake that struck in mid-August, killing more than 2,200 people and destroying tens of thousands of homes.