"People are dying and the authorities do not care at all," said Mimose Targette, a leader at the same church where Sister Isabel Sola Macas, 51, played guitar every morning.
Macas was driving in downtown Port-au-Prince early Friday when she was gunned down by unidentified attackers who shot her twice in the chest - a shocking act even in this poverty-stricken and politically insecure nation where acts of violence are not uncommon.
The passenger next to Macas was also hit and is still receiving treatment in a hospital in the capital city.
"Sister Isa helped people from poor neighborhoods and these are the same people who killed her," Targette said.
Top religious leaders as well as everyday citizens filed past her open coffin Thursday and offered condolences to her four siblings who came to Port-au-Prince for the funeral.
Haitian police said progress had been made in the investigation but declined to share any details.
"We know that the investigation will lead to nothing, so it's still one more person who has spilled her blood for nothing," Catholic sister Sandra Thomas said.
"But we are going to continue fighting in our own way so that Haiti finally rises from the ashes because we are not going to leave this country by itself," she added.