Migori Governor Okoth Obado, his personal assistant Michael Oyamo and Nation journalist Barrack Oduor were grilled by police on Tuesday on the murder of Rongo University student Sharon Otieno.
They were questioned at Nyanza regional police headquarters, where Mr Obado remained for at least eight hours. The Governor underwent DNA tests.
Mr Oyamo and Mr Oduor waited in different cars outside the police station, under tight security, as Mr Obado faced the investigators.
The Governor's lengthy grilling attracted onlookers who waited to catch a glimpse of him; he appeared in public for the first time after being mentioned adversely in the matter.
The county chief was whisked away from the DCI offices by police.
His legal team, which includes lawyers Cliff Ombeta and Rogers Sagana, declined to explain why he left the station in a police car.
Mr Ombeta said his client cooperated with the investigators and that he will defend himself against any allegations concerning Ms Otieno's death.
"Our client was not arrested. He came here to give his statement and that is what he has done," he noted.
The homicide team took less than two hours to record Mr Oduor's statement.
The team dispatched by DCI director George Kinoti collected the clothes the journalist wore when he and Ms Otieno were kidnapped.
A DCI officer, who sought anonymity, said Mr Oduor and Mr Oyamo will be handled by the joint security forces also handling the Governor.