It happened in Burlington Junction shortly after 11 a.m. at Citizens Bank & Trust located at 102 Oak Street.
Authorities say two men entered through a back door, showed a firearm and demanded money.
They got away, but not without being seen by a man working in an office two doors down from the bank. He called Nodaway County Sheriff Darren White.
"If it were not for the man that called me on the phone, we would not have these guys in custody right now," said White. "He gave us a good description and then he proceeded to follow them, not chase them, but he followed them. He kept me apprised of where they were at all times until we could get law enforcement in the area."
The chase included county and state law enforcement along with the FBI.
Sheriff White was part of a foot chase that finally led to the suspects' arrest near the Iowa border after they got out of their car and ran into a wooded area.
The three are believed to be from Iowa, but they are not talking to deputies.
Sheriff White says around $10,000 was taken from the bank, but to this point, only an empty money bag from the bank has been found.
He hopes to have an identity of the three suspects by tomorrow at the latest.