Police sources said the owners were using the money to con people.
"It’s fake and was found inside a safe in the bank," the sources said adding that they are currently investigating the matter.
The bank in a statement said a customer who holds a personal safe deposit box at our Queensway branch was the one intercepted.
"Police are currently investigating the contents of his safe deposit box. We are assisting the authorities to investigate this matter fully," Barclays said.
The six suspects are:- Dr. Erick Adede-Owner of the Box, Mr. Ahmed Shah- Fake Investor, Ms. Elizabeth Muthoni, Ms. Irene Wairimu Kimani, Mr. Boaz Ochich - Bank official, Mr. Charles Manzi - Bank official.
Also held for statement recording is a witness who would have been conned.