Local authorities responded to a situation at First State Bank and Trust's downtown location at about 2 p.m.
Crime tape surrounded the building and detectives inquired at businesses nearby about exterior surveillance cameras.
A witness who called 911 from the scene said he tried to enter the bank as it appeared to be in the process of a robbery before walking down the street to the Fremont Tribune around 2:15 p.m.
Richard Crooks told the Tribune that locked doors prevented him from entering and that the tellers inside looked "somber."
"I just thought it was a bank examination they had to finish, and then they handed this guy a big bundle of money, and I thought, 'Well maybe it's when they do big cash transactions, they don't want people in,'" he said. "When the head guy came over and shook his head at me, I went, 'I think that might be more than what I think it is.'"
Crooks, who is the pastor for First Baptist Church, said he couldn't get a good description of the suspect, but identified him as a tall white male who wasn't covering his face.
"The angles I was at, I had no idea if he had a weapon or not," he said. "And I wasn't going to stay around and find out either."
Nearby businesses said they heard no gunshots or sirens around the time of the incident.
Cindy Slykhuis, vice president of marketing for First State Bank and Trust, said the bank has no comment at this time due to "ongoing investigations."
A suspect is described as a tall white male, bald, with glasses. He was seen getting into a blue four-door car and leaving the scene, according to the Fremont Police Department.
He displayed a weapon and then fled the bank with an undisclosed amount of money. No customers were in the bank at the time of the incident and no employees were injured.
This is a developing story.