The woman, her fiancé and his brother had been shopping for her wedding scheduled for Saturday when three gunmen confronted them inside a shop at Corner House, and pumped bullets into her head.
Central divisional police Chief Patrick Oduma said the fiancé was unhurt and nothing was stolen from them.
“This incident occurred at around 4pm whereby the bride and the brother to the bridegroom had come to buy a ring. The couple was set to marry on Saturday at a church in Mathare North,” he said.
“Unfortunately before they gave out money for the ring they had identified, three men armed with a pistol pounced in and shot the bride and the brother to the bridegroom and immediately left.”
The woman died instantly but her brother-in-law was rushed to the Kenyatta National Hospital after sustaining bullet wounds to the head.
Police said they believe the attackers were on a killing mission.
“We have launched investigations to why this could happen in this manner. The intention was not to steal,” he stated.
“According to us, this is a total assassination or murder; we are going to follow up the matter and bring to book whoever is involved.”