Mathira MP Rigathi Gachagua is at the DCI headquarters after being summoned on Monday to answer to accusations of alleged embezzlement of Sh12 billion in public funds.
He is being grilled by Serious Crime Unit detectives.
This comes days after his accounts were frozen as part of the ongoing probe.
Detectives have been investigating how more than 20 firms linked to the MP were used to secure tenders in several counties.
Rigathi has previously maintained that he is innocent, adding he is a businessman who has acquired wealth over the years.
More follows...