“Cops have feelings, too”

In the week after Officers Ramos and Liu were killed on Dec. 20, the number of summonses for minor criminal offenses, as well as those for parking and traffic violations, decreased by more than 90 percent versus the same week a year earlier. And arrests over seven major categories of felony offenses were nearly 40 percent lower, the numbers show.

“Police do have some discretion, and sometimes they use it in waves,” said Dennis C. Smith, a professor of public policy at New York University, who has studied Operation Impact, one of the department’s signature initiatives.

Michael J. Palladino, the head of the Detectives’ Endowment Association, said that while a stoppage was not sanctioned for detectives, in his opinion it was understandable.

“Cops have feelings, too,” he said. “Now they are the targets of execution. That’s enough to make anyone hesitate, regardless of your profession.”