Four officials from the Kerio Valley Development Authority (KVDA) were on Monday arrested and are presently being detained at Central Police Station in Eldoret.
Detectives raided the KVDA headquarters in Eldoret and arrested the acting Managing Director Francis Kipkech, who is a member of the tender committee.
Also arrested are KVDA tender committee members Patrick Kiptoo and David Juma Onyango, and Charity Muui, a clerk for the Ad hoc Technical and Evaluation Committee.
Detectives from the Directorate of Criminal Investigations (DCI) had earlier raided the KVDA offices in search of former Managing Director David Kipchumba Kimosop.
The search was however fruitless as Mr. Kimosop was not in the premises and his location remains unknown.
Presence of the detectives at KVDA shortly after Mr Haji made the arrest orders caused a stir and panic among staff.
Some of the suspects, however, escaped the police dragnet during the 11am raid.
The detectives are now hunting for 13 KVDA staff implicated in the dams scandal that saw taxpayers lose Sh21 billion paid out to a bankrupt Italian firm for the projects which never took off.
Those arrested were taken to the Eldoret Central Police Station awaiting to be transferred to Nairobi for arraignment.
The suspects face eight charges of economic crimes.