It all started with a sick nurse, whose positive test for Ebola came only after her death. In a busy clinic that treats Mali's elite as well as wounded UN peacekeepers, who was the patient who had transmitted the virus?
Soon hospital officials were taking a second look at the case of a 70-year-old man who had died after being brought to the capital late at night from Guinea suffering from kidney failure.
A friend who visited him had later died under suspicious circumstances, too.
It wasn't renal disease, they then realised. The 70-year-old man had Ebola and all three of the relatives who brought him to the clinic that night had all since been admitted to an Ebola treatment center back home in Guinea, too.
On Friday, Malian health authorities went to disinfect the mosque where the 70-year-old's body was prepared for burial -- nearly three weeks ago.
Already some are criticizing the Malian government for being too slow to react when health authorities had announced his death as a suspected Ebola case earlier in the week.
"It's been 18 days since the Guinean man sick with Ebola died here. It's just too late," said Koumou Keita, his face full of worry.
For nearly a year, Mali had been spared the virus now blamed for killing more than 5,000 people across West Africa despite the fact the country shared a porous land border with Guinea, the country where the epidemic first erupted.
Now there are least three confirmed Ebola deaths, and two others suspected deaths in Mali's capital, Bamako. Residents here who have seen the carnage from Ebola in neighboring Guinea now fear the worst.
"I feel uneasy because I have the impression that our authorities are not giving us the whole truth," said Ibrahim Traore, who works at a supermarket in the capital.
"There are a lot of things not being said about how the Ebola virus came to Bamako."
Health officials now must try to track down not only family and friends who visited the 70-year-old man at his hospital bed, but also the scores of people who prepared his body for burial and attended his funeral.
Teams of investigators are also headed to the border community where authorities believe the Patient Zero in the Bamako cluster -- the 70-year-old man -- first fell ill.
