Authorities say the suspect, Michael Wheeler, has robbed four banks in the last two weeks.
Marple Township Police Department, Delaware State Police, and Middletown (Del.) Police Department are also working with the FBI to find Wheeler.
The four banks are:
July 29, 2019 - Wells Fargo Bank; 2701 West Chester Pike, Broomall, Marple Township, Pennsylvania
August 2, 2019 - WSFS Bank; 105 Irish Hill Road, Felton, Delaware
August 5, 2019 - M&T Bank; 399 East Main Street, Middletown, Delaware
August 5, 2019 - Wells Fargo Bank; 814 Philadelphia Pike, Wilmington, Delaware
Wheeler is under investigation for an additional bank robbery in Pennsylvania, a bank robbery in New Jersey, and a bank robbery in Maryland, as well.
Authorities say Wheeler also attempted to rob a TD Bank in the 2500 block of Marsh Road in Wilmington, Delaware on Thursday but got no cash.
Police say in at least one robbery Wheeler handed the teller the note and implied he had a gun.
Those in the area that have heard about robberies say hope Wheeler is captured soon.
"This kind of activity I'm concerned about it, really scared," said nearby business owner Tony Causi. "Hopefully, they catch him," said Craig Voll from Newark.
Wells Fargo Bank is offering a reward of up to $1,000 for information leading to the arrest.
This subject is considered armed and dangerous. Anyone with information about Wheeler's location is asked to call the FBI at 215-418-4000. Tipsters can remain anonymous.