Federal agents from the Drug Enforcement Administration and the criminal investigation division of the IRS were seen inside the former Alex Brown Building at One South Street on Wednesday afternoon.
An IRS agent appeared to be standing guard inside the lobby near the left elevator. Joy Cuffee, a Special Agent with the IRS, said that agents were there on "official business" and declined to elaborate.
DEA Special Agent in Charge Gary Tuggle confirmed his office was also involved, but also declined to say why or what business or individual was being investigated.
Some workers declined to comment as they left for the day; others said they did not know which offices the agents had raided.
The building is home to a number of prominent businesses, including several law firms, investment banking and real estate companies.