Public Service Principal Secretary Lillian Mbogo-Omollo and National Youth Service (NYS) boss Richard Ndubai are among 29 government officials who could be arrested after they were questioned by police.
Others include a chief accountant, head of procurement, principal accountant, head of accounts and the financial and economic officer at NYS.
Treasury officials are also facing arrest after police narrowed down to questionable payments paid through the Integrated Financial Management Information System.
Fourteen directors of 10 companies that did business with the NYS were also interrogated by police detectives.
The Director of Criminal Investigations, Mr George Kinoti, said: “Of all those whose statements were recorded, we are preparing to make at least 30 arrests. They will have their day in court and none will be spared, irrespective of their rank. Public money was stolen and the suspects must be charged.”