Security analyst Mwenda Mbijiwe has weighed in on a mystery letter warning about an alleged plot to assassinate Deputy President Dr William Ruto.

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Speaking on Thursday on a panel interview on the Kenya Television Network (KTN), Mr Mbijiwe wondered why the Kenyan authorities were seeking the help of the Federal Bureau of Investigations (FBI).

"I am thoroughly amused like any other Kenyan to know that this could be happening in the heart of government, touching the most critical people in this administration... This thing about the FBI, do we have to go that far? Don't we have finger-printing technology and forensics in this country? Did we really have to get some FBI experts to find out if a signature was faked or not?" asked Mr Mbijiwe.

The Directorate of Criminal Investigations (DCI) boss George Kinoti said that the investigative body was treating the mystery letter with a lot of seriousness and that investigations to determine its author were firmly on course.

"We are treating that letter seriously and investigators want to ascertain its origin and authenticity. Once we know the source of the letter and how it came to existence, we shall focus on the authenticity of the issues raised," said DCI Kinoti as quoted by the Nation.