An unspecified amount of money was taken from the M&T Bank branch office in the city's Newberry neighborhood about 4:30 p.m. Friday.
According to city police, one suspect was detained at the scene and taken to police headquarters for further questioning.
"We're expecting to take him in to be arraigned later this evening," city police Sergeant Kristopher Moore said.
This is the second robbery to occur at the branch this month. On Dec. 4, a masked man walked into the office and made off with an undisclosed amount of cash in a gray bag, according to police.
No arrests have been made for the first robbery.