A memorial service for the late NHIF staff Lilian Waithera was on Tuesday held at the Kariobangi South Catholic Church, Nairobi.
Waithera was shot on the evening of February 13 as she walked along Kaunda Street by a suspected sniper.
Initially, police and pedestrians believed the 46-year-old clerk at the National Health Insurance Fund collapsed and died out of natural causes.
But an autopsy indicated that she died from a shooting after a bullet was found lodged in her lungs.
On Tuesday, police said they had arrested a man they suspect fired the fatal shot.
The licensed gun holder was traced to his home in Kenol, Murang’a. He was disarmed and the weapon has taken for ballistic analysis.
Waithera's shooting and death read like a script for movies.
On a fateful day, she had walked from her workstation in Upper Hill in the company of a workmate.
On reaching Kaunda Street at around 5.30 pm, she was suddenly startled, held her chest and said something had hit her. She gasped for breath and collapsed.
Her colleague called for an ambulance. Waithera was bleeding from her mouth but had no physical signs of injury on her body. She died at the scene.
Police said in their report that the shooter discharged the killer bullet from an elevated area, presumably a highrise building in the vicinity.
"Autopsy revealed the bullet was lodged in her lungs. The bullet entered through the collar bone, having been fired from an elevated angle."
The scene of the shooting is surrounded by Eco Bank Towers, Dream Bean House, Almandi Yemeni House, Hamilton House and Jubilee Insurance Building.
The suspect in custody told police he was in the CBD on the day of the shooting but he never used his weapon.
Police suspect he discharged the gun by mistake.
"He says he never went up to any of the floors at the building and he allegedly went and placed the weapon in his car before leaving," a senior officer aware of the probe said.
Part of the investigations revolve around placing the suspect at the scene of the shooting.