National Treasury Cabinet Secretary Henry Rotich on Wednesday evening left the Directorate of Criminal Investigations (DCI) after enduring a 10-hour grilling session over the controversial construction of two dams in Elgeyo Marakwet.
This was the second straight day that Mr Rotich has been questioned by the George Kinoti-led directorate.
He is under scrutiny for authorising payment of Sh20 billion to facilitate the building of Arror and Kimwarer dams in Elgeyo Marakwet County.
"The reason why it took long is because we are dealing with international contracts which take time to understand. It took a while for investigators to understand how international contracts work," Mr Kigen said as he drove away.
Mr Rotich arrived at the DCI some few minutes after 8am, and his vehicles drove out of Mazingira House, where the session was held, at exactly 8.45pm.
His lawyer Katwa Kigen said his client answered all the questions. "We have completed supplying the information sought by the investigators and we trust the issues are clear."
The Kerio Valley Development Authority (KVDA), which contracted Italian companies CMC di Ravenna and Itinera, is also at the centre of investigations for allegedly paying kickbacks to some individuals to win the Kimwarer and Arror tenders.
On Sunday, Mr Rotich defended himself in a newspaper advertisement trying to justify the Sh20 billion paid in advance for the construction of the dams.
In so doing, he contradicted claims by Deputy President William Ruto that only Sh7 billion had been paid out.
Mr Rotich said that up to Sh19.8 billion had been paid to different firms on various dates by end of last year.
The amount is Sh1.2 billion short of the Sh21 billion the DCI is pursuing, and Mr Rotich said the payments were largely fees issued as part of the conditions to be met before construction started.
Mr David Kimosop, KVDA managing director, and several board members have been questioned four times.