A senior police officer attached to the Anti-Terrorism Police Unit collapsed and died on arrival at the Jomo Kenyatta International Airport (JKIA) in Nairobi.
Chief Inspector Monica Wambui Githaiga had arrived at JKIA from Japan where she has been attending a short training course.
She had connected from Japan through Dubai and Addis Ababa aboard an Ethiopian airline flight.
Police said Ms Githaiga had complained that she was feeling unwell in Dubai. She was attended to before being allowed to board her flight to Nairobi, which touched down on Saturday afternoon.
She told her colleague that she was experiencing chest pains and dizziness. Witnesses said she vomited before receiving medical assistance from medics at the Port Health Clinic situated inside the airport, where she passed on.
A post-mortem has been planned to establish the cause of her death.
Her colleagues described her as a dedicated officer. Githaiga has been the lead investigator in the dusitD2 Hotel attack which occurred on January 15 and in which 21 people were killed.
In court testimony, she narrated how one of the suspects in custody over the terror attack received Sh9 million from South Africa. The money was withdrawn using mobile money transfer and later through a local bank.
Police suspect the money was for financing terrorism.
Githaiga had testified that the suspect registered 47 SIM cards using different identity cards and names. The SIM cards were used in two handsets that were geo-located in Eastleigh area, Nairobi.
The case is still pending in court.