Another police officer was murdered recently. He was Capt. Robert Melton of Kansas City, Kansas, gunned down as he was approaching suspects in a drive-by shooting. His death brought to 18 the number of law enforcement officers killed in the line of duty this month.

Eight of them were killed in two tragedies in Dallas, Texas, and Baton Rouge, Louisiana. They were murdered by two men allegedly upset about the deaths of black males at the hands of police.

But 10 of the line-of-duty deaths involved “normal” activities by police and corrections officers. That raises a question that ought to be very disturbing:

Calls for retribution against all law enforcement officers because of the deaths of black men may have spurred those involved in the Dallas and Baton Rouge shootings. But have they also emboldened others who murder solely in the course of other criminal activities?

Killings of on-duty law officers seemed to be on the decline for a few years, dropping from 180 in 2011 to 139, 123, 145 and 130 in succeeding years, respectively.

But already this year, 69 have died while serving and protecting.

Murdering a police officer is viewed by right-thinking people as among the most heinous of crimes. They regard such acts as deserving of the most severe punishment available. That is appropriate.

Anyone who, for whatever reason, believes that no longer is the way virtually all Americans feel is very, very mistaken.