In the popular imagination, there are multiple candidates for the symbolic end of the 1960s. Some might say that the chaotic and confused decade ended with the deaths of four attendees at the Rolling Stones’ concert at the Altamont Speedway in December 1969, while others could point to the United States’s withdrawal from Vietnam in March 1973.

The death of far-left militant and convicted murderer Kathy Boudin, however, points to a far later endpoint to the convulsions of the ’60s: On Oct. 20, 1981, Boudin was among a trio of leftist radicals previously associated with the Weather Underground who, in tandem with members of the Black Liberation Army, executed a robbery of an armored car truck in Nanuet, New York. Between the robbery itself and a subsequent encounter with police, three people — Brink’s guard Peter Paige and members of the Nyack police department, officer Waverly Brown and Sgt. Edward O’Grady — were killed.