Why Didn't NYPD Officer Ryan Nash Kill New York Attacker Sayfullo Saipov?

An NYPD officer stands guard at a crime scene near a bike path where a body is covered with a white sheet in lower Manhattan, on October 31. A New York City police officer used deadly force to stop a terror suspect Tuesday but did not kill him. REUTERS/Brendan McDermid

A New York City police officer used deadly force to stop a terror suspect Tuesday but did not kill him, raising possible questions about the final moments of an attack that killed eight people and injured 13.

Officer Ryan Nash, a 28-year-old who has worked for the department since 2012, shot suspect Sayfullo Saipov in the abdomen after Saipov exited his vehicle carrying weapons that turned out to be a pellet gun and a paintball gun. Saipov was wounded, and, as of Wednesday morning, was out of surgery and in custody at an unidentified hospital, according to CNN.

The NYPD patrol guide, which is posted on the department website, instructs officers to "apply no more than the reasonable force necessary to gain control," and to use de-escalation techniques to avoid excessive force. Officers are trained to use minimal force to stop even potentially deadly assailants, but cops must make split-second decisions that require them to determine who is a deadly threat and who is not. Saipov's weapons clearly suggested an imminent threat.

Many officers in similar situations have followed the patrol guide and shot, only to find themselves later charged with using excessive force. In the moment, the officer likely is not thinking about the ramifications of using deadly force, but scrutiny after the fact often centers on why and how the cop fired.

The NYPD did not comment for this story, but the head of a national police organization said it is premature to question Nash's response to the attack, adding he followed his training to focus on "neutralizing the threat."

"[Police officers] don't go into it with the idea of thinking about killing somebody," said Darrel Stephens, executive director of the Major City Chiefs Association, which represents sheriffs and chiefs of police in the nation's largest metropolitan areas (including New York). "They're thinking about neutralizing the threat."

Stephens added that most police officers are trained to shoot "center mass" to stop a threat—meaning the chest area—because it increases the likelihood the shot will hit the suspect and stop them. That's where Saipov was allegedly hit.

A shot near the chest sometimes kills the suspect, but it's not always the case.

Publicly, the NYPD is only hailing Nash's efforts. At a press conference on Tuesday, New York City Police Commissioner James O'Neill commended Nash because he "stopped the carnage moments after it began."

New York Mayor Bill de Blasio thanked the NYPD, "starting with the officer [Nash] who stopped this tragedy from continuing."