SEPTA officials say the attack occurred Monday around 9:30 a.m. at the Frankford Transportation Center.
Neither the agent nor the man who was punched have been identified. In the roughly six-second video, a SEPTA police officer rushed over to the two as the man struck appeared to get up.
SEPTA officials said the job of a revenue agent is to collect cash from fare kiosks and cashier booths throughout the system.
While revenue agents are not a part of the SEPTA Transit Police Department, they are authorized to carry firearms due to the nature of their job.
SEPTA investigating after employee punches a man
"An arrest was made of that revenue agent. The revenue agent was given the opportunity to give a statement," said SEPTA Police Chief Thomas Nestel III. "It was determined that further investigation was necessary before charging or requesting charging from the DA's office."
The agent has been placed on administrative duty pending the outcome of the investigation.
"That investigation should be cleared up in the very near future," Nestel added.
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