The incident occurred on July 10, 2026, at around 4:30pm on the ground floor of the commercial building, according to Kampala Metropolitan Police.
Preliminary investigations indicate that the confrontation began after the hawker was asked to leave the premises by a security guard.
The disagreement reportedly escalated into violence, with the guard allegedly stabbing the hawker in the chest.
The victim collapsed and was pronounced dead at the scene.
Police identified the suspect as Ian Mugisha, a security guard attached to Security 2000. He was arrested immediately after the incident, and detectives recovered the suspected murder weapon.
The deceased's identity had not been established by Monday. The body was taken to the KCCA City Mortuary for a post-mortem examination.
Kampala Metropolitan Police said investigations are ongoing to establish the full circumstances surrounding the fatal stabbing.
"We have commenced investigations to establish the full circumstances surrounding the incident," Kampala Metropolitan Police Deputy Public Relations Officer ASP Luke Owoyesigyire said in a statement.
Police said further updates will be provided as investigations progress.