Letter Carrier Garrett Smola was picking up a package recently in Springfield, MA, when he heard yelling nearby.
Smola looked around and spotted a younger man beating an older man and demanding his wallet.
The Postal Service employee safely intervened, ordering the assailant to stop, at which point he fled the scene.
Smola called 911 and stayed with the victim, a retired doctor, until emergency responders arrived.
The man, who is recovering after an extended hospitalization, later contacted the local Post Office to thank Smola for his life-saving intervention.