National Youth Service (NYS) Director Richard Ndubai has been arrested.
Ndubai has been nabbed alongside three officials in the ongoing probe on the theft of Sh9 billion.
The others are assistant director general Sam Michuki, finance manager Mr Mbugua, and a fourth official whose name is yet to be established.
According to reports, the four were arrested on Sunday and will be taken to the DCI headquarters for questioning before being taken to court to face various charges related to the NYS scandal.
Ndubai, who stepped aside a week ago to pave the way for investigations into the scandal, was arrested on Sunday night alongside 20 other suspects and taken to Muthaiga Police Station.
The 16 suspects are said to have been arrested in Nairobi while four were nabbed in Naivasha.
Reports indicate that those arrested include NYS officers and alleged suppliers who benefited from fraudulent procurement deals with the youth agency.
Youth Affairs Principal Secretary Lillian Mbogo-Omollo, who stepped aside alongside Mr. Ndubai, was also set to be arrested at her Nairobi home but surrendered to the DCI detectives accompanied by her lawyers.