38-year-old Bakari Tsuma was accosted by the criminals while walking home alongside his wife, with whom they had reportedly gone out for dinner.
Confirming the incident, Nairobi Police Commander Japheth Koome said the officer was shot in the forehead, after which the thugs made away with his pistol.
According to the deceased's wife, immediately after the incident she sought for help and managed to rush her husband to Nairobi Hospital but he was pronounced dead upon arrival.
The Nairobi Senator expressed his grief over the incident, urging police to hasten investigations to unravel the mystery around the killing.
“It is a major blow to my security team, his family and the entire police force. I urge top police officers to immediately conduct the investigations, bring those involved to book and recover the stolen pistol.” Sonko said in a press address.
Sonko further expressed concern over the manner in which the assault was carried out, adding that he now feared for his life.
“We want to know how and why my bodyguard was killed. These seem to be professional people on a mission,” he said.
The slain officer is set to be laid to rest on Monday at his home in Golini area, Kwale County.