Detectives have zeroed in on former Nairobi Governor Evans Kidero and impounded his top of the range car.
According to reliable sources, the sleuths are holding a Mercedes Benz 500E which they suspect has a fake registration number plate as well as suspicions it was smuggled into the country.
"We want to establish if there was a plot to evade tax. Not paying taxes is a grave illegality," the investigator said.
“It beats logic why a former governor can deliberately fail to pay tax, then go ahead and have a fake registration plate on his car,” he added.
The car is currently being held at the Parklands Police station.
Kidero has reportedly being grilled over the issue.
The ex-governor is among opposition leader Raila Odinga's allies. He won the Nairobi top job on an Orange Democratic Movement party.