According to witnesses and police, she had complained of chest pain while walking and collapsed soon after.

Her colleagues called an ambulance, which arrived quickly, but Waithera could not be revived, and she was declared dead at the scene.

The police were called to the scene and launched an investigation into the incident.

More on this story

Puzzle of mysterious shooter behind NHIF staffer's death in Nairobi CB...

• Family of NHIF staffer shot in Nairobi CBD speaks
• CCTV footage unearths new details in the shooting of NHIF staffer in Nairobi CBD
• Sniper's bullet: Who wanted her dead? The riddle of a murder
• 27 hospitals suspended over Sh171m NHIF fraud

Nairobi police boss Adamson Bungei said that the police had taken the body to the mortuary, where it would be examined further.

He also stated that they were investigating the incident, and more details would be revealed soon.

On Tuesday, the police stated that they suspect Waithera had been shot from an elevated angle shortly before she collapsed.

Her colleagues did not report hearing any gunshots in the area when she collapsed.

The report indicated that the bullet was lodged in her lungs, and it was discovered during an autopsy conducted at the Kenyatta University Motuary.

“The female NHIF staff who collapsed and died along Kaunda Street on Monday evening had been shot from an elevated angle. Autopsy revealed the bullet was lodged in her lungs,” the report by the police read.

According to the police, the bullet had entered through the collarbone, indicating that it had been fired from an elevated angle.

The family and friends of Ms Waithera have called for a speedy investigation into her death, urging the police to find those responsible for the shooting.

The shooting has raised questions about security in Nairobi central business district, with many concerned about the safety of workers and residents in the area.

The incident has also highlighted the need for tighter security measures and improved surveillance systems in the city.