Ray Vega was taken into custody on Thursday and will likely be charged with conspiracy and robbery. He has since posted $100,000 bail and was released from custody.
Eyewitness News has learned that Vega is the bank manager's boyfriend.
Police did not release any further details, saying the investigation was ongoing.
Authorities were called to the bank on Sept. 5 after the branch manager arrived at work with a device she believed was a bomb strapped to her body. She told detectives she was leaving her Huntington Park house on her way to work when she was kidnapped by two masked men. She said the armed robbers ordered her to go the vault, get the money and throw it out the side door.
The suspects got away with what officials call "a significant amount of money." The bomb squad arrived quickly and removed the device from the manager. They determined it was not an explosive, but was made to look like one.