Bangor Police say Ronald Tilley allegedly robbed Downeast Credit Union's Springer Drive location last month.
They say he threatened employees and fled with an undisclosed amount of money.
Two weeks ago, while police in Bangor were searching for Tilley, police in North Stonington, Connecticut arrested him on a shoplifting complaint.
Tilley remains behind bars at the Penobscot County Jail.
The district attorney's office is expected to seek a robbery indictment against Tilley at the next session of the Penobscot County Grand Jury.