Surveillance footage from a liquor store near the Chick-fil-A in Boston’s Copley Square captured the “traumatizing” moment when dozens of people sprinted away after an off-duty police officer shot and killed a man wielding a knife inside the restaurant on Saturday evening.

Security footage obtained by the Globe shows a panicked crowd fleeing the Chick-fil-A restaurant in Copley Square Saturday evening at about the time an off-duty police officer shot and killed a person police say was wielding a knife and trying to stab people.

The Boston Police Detectives Union praised the actions of an off-duty officer who authorities say shot and killed a knife-wielding suspect​ inside a city Chick-fil-A.