The bodyguard was shot in the shoulder and his gun was taken as he was buying pots of flowers by the side of the road, Mohamed said.
The High Court has dismissed a petition seeking to compel National Super Alliance (Nasa) leader Raila Odinga to take part in the Thursday repeat presidential election.
One of the candidates who fought the election in August, Raila Odinga, is boycotting the vote, claiming Kenya's election board has made insufficient progress to ensure it will be free and fair. Violence has broken out between police and protesters as authorities banned demonstrations in Kenya's largest cities last week.
"It happened so fast, the guy just jumped off the motorbike and sprayed him with bullets", the officer said.
Kenyatta officially won the first election on August 8, by 1.4 million votes, but the Supreme Court annulled that outcome on September 1 over procedural irregularities.
Wednesday has been unexpectedly declared a public holiday, but the Supreme Court says that will not affect its business.
South Park: The Fractured But Whole details its season pass
There's not much in the way of information on this one just yet, but it will, says Ubisoft, introduce an all-new superhero class. Releasing sometime in 2018, the player must "team up with The Coon and Mysterion to defeat a demonic presence at Casa Bonita".
Justice Chacha Mwita on Tuesday afternoon ruled that issues raised by Pokot South MP David Pkosing fall under the jurisdiction of the Supreme Court.
One key case, brought by human rights activist Khelef Khalifa and two others, seeks to delay the vote on grounds that the election board is not sufficiently prepared.
Kenyan President Uhuru Kenyatta on Sunday led the country in national prayers, calling on Kenyans to maintain peace ahead of the October 26 repeat presidential elections.
According to a special gazette notice signed by Acting Interior Cabinet Secretary Fred Matiangi, this will enable Kenyans prepare to participate in the fresh presidential election set for Thursday.
Ahead of the planned vote on Thursday, the European Union said it would have a reduced number of election observers, citing the tense political environment and concerns about the safety of its monitors.
IEBC chairman Wafula Chebukati's announcement that the election may not be credible has fulled calls that the exercise should be cancelled.