Authorities say Metro Bank manager David Parsons swiped $196,000 from the customer's account between March and August of last year.
Berks County detectives say the Exeter Township branch manager monitored the jailed victim's account for several months before taking the money. Investigators say the victim had inherited the money.
Detectives say Parsons created debit cards using the victim's personal information then used them to make maximum daily withdrawals from ATMs in Berks and Lebanon counties.
Parsons' attorney says his client is cooperating with authorities.
Investigators didn't identify the victim but court documents indicate he was in custody of immigration authorities.