A senior manager at the branch as arrested on Sunday as a key suspect and interrogated before he was released on police bail on Tuesday.
Detectives from the Directorate of Criminal Investigations (DCI) in Turkana County are investigating the loss of Sh22 million from the KCB Bank Lokichoggio branch.
Preliminary investigation show that Sh22.7 million was lost at the bank between October 2017 and March 2020.
Turkana County Criminal Investigation Officer James Lelia confirmed that a senior manager at the branch as arrested on Sunday as a key suspect and interrogated before he was released on police bail on Tuesday.
Mr Lelia said that the suspected fraudulent incident was exposed after a top KCB investigator, who is based in Nairobi reported the matter.
Detectives said an anomaly at the bank was noticed by a new branch manager last month. The manager did cash surprise checks at the bank's safe counted all the available cash and compared against the ledger book and noticed a discrepancy.
"The new branch manager discovered from the cash surprise checks that a total of Sh. 22.7 million was missing," Mr Lelia said.
The detectives arrested the senior official who has been working as there since 2013 after he failed to account for the missing money.
"Even as we still hold the key suspect who may not be taken to court immediately, we also need to trace the whereabouts of a former for interrogation," the Turkana County Criminal Investigations Officer said.
Mr Lelia said prosecution of the case will take a long time because of the coronavirus outbreak.
The suspect was released on medical grounds after the court said the matter was not urgent after the Judiciary cut down operations in a bid to keep safe staff from contracting coronavirus.
"Our key suspect has already been released from Kakuma Police Station on cash bail to seek medication but investigations are still on," he said.