The money was recovered at a house in Mwiki, in the outskirts of the city where a man and woman believed to be a couple was arrested following a tip off from the public, according to the police.
“We are holding the two suspects who were found with a large sum of money,” a Flying Squad detective involved in the search told Capital FM News.
The couple was picked up on Tuesday morning when officers raided the house.
The suspects and the recovered money were immediately moved to the Nairobi Area Provincial Police headquarters where bank officials joined the officers in verifying the cash.
“There is nothing to hide. The operation involves bank officials and everyone is satisfied with the work the police are doing,” another officer said.
Nairobi Provincial Police chief Antony Kibuchi confirmed the arrests and recovery but he did not give further details.
“The suspects are being interrogated to know if they were in any way involved in this robbery,” he said.
Police said the money was stolen when thugs disguised as guards from a local security firm drove in and headed to the strong room.
Police said they would interrogate neighbours of the couple found with the large sum of money to give further information on their activities.
“We have taken their fingerprints to help us establish if they match those left at the scene of the robbery,” a police officer said.
Police were considering setting free the woman arrested with the man in Mwiki.
“If it turns out she is his wife, there is a possibility she is not an accomplice. That decision cannot be made now,” he added.