The robbers are said to have gained access by drilling a hole into a wall leading to the bank’s safe.
None of the security guards manning the bank knew about the incident until Sunday morning.
Police said they took away an ATM machine containing money and the safe.
A night guard was detained following the theft of an ATM and a safe loaded with cash at Equity Bank in Kayole on Saturday. The Jamka Security Services staff member, identified only as Mwangi, was arrested on Monday
New safes that were taken to Equity Bank in Kayole.