Kiambu Governor Ferdinand Waititu's wife Susan Wangare is among 14 people who have been arrested over illegal construction of buildings in Nairobi.
Wangare was apprehended on Wednesday alongside contractors who worked on the renovations of the Jamii Bora building and Delta Hotel.
The arrest came amid the National Environment Management Authority's efforts to reclaim riparian reserves.
A multi-agency team has been demolishing multi-billion shillings property on the reserves but there have been complaints by some members of the public.
Waititu earlier said that instead of the destruction, property owners should be forced to "divert rivers". He also said Nema and Nairobi county should look for alternative to the demolition.
Nairobi Governor Mike Sonko told him to keep off the capital's matters.