'The mayors [sic] hands are literally dripping with our blood because of his words, actions and policies, and we have, for the first time in a number of years, become a 'wartime' police department."

These words, purportedly in an email from Patrolmen's Benevolent Association president Patrick Lynch to the city's 35,000 cops, followed the assassinations of Officers Wenjian Liu and Rafael Ramos in Brooklyn. The NYPD said they were shot by Ismaaiyl Brinsley, an African-American with an arrest record who said on social media he was avenging the deaths of Michael Brown in Missouri and Eric Garner in Staten Island.

Lynch's email, seeming to blame Mayor Bill de Blasio for the killings, may sound harsh, but it reflects the feelings of many in law enforcement. Two former NYPD deputy commissioners, both of whom asked for anonymity to speak candidly, said separately that de Blasio has "created" a climate that encouraged the killings.

Let's recall some of what de Blasio has done: embraced the controversial Rev. Al Sharpton; refused to criticize a former adviser despite her boyfriend's and son's social-media rants against cops; and announced that he told his son, Dante, that as a biracial teen he must be wary in encounters with police.

And it's not just de Blasio who contributed to the climate, says Lou Turco, head of the Lieutenants Benevolent Association. "Our elected officials have irresponsibly added to an incendiary atmosphere of distrust against law enforcement."

Last, there is the national media, which after the Brown and Garner deaths concocted a narrative of brutal white police officers and victimized black men that tells half the story. The media missed the chasm between cops and communities they serve, including the violence in black neighborhoods police face daily.

Unless the mayor and the NYPD come together, the legitimate grievances of police brutality victims will be lost -- from unlawful stop-and-frisks to the poor tactics that led to Garner's death. Perhaps the mayor can deal with the climate he helped create by apologizing for some of his words and deeds. Perhaps, too, Lynch might walk back some of his remarks.

Lynch may have already done so. Lynch's email was provided to me by a retired chief. However, on Monday, Lynch's spokesman denied that the email came from the union president. However, when amNewYork left a phone message on Saturday with the PBA spokesman to authenticate the email, the spokesman did not return the call.

Will either the mayor or union leader backtrack publicly? Don't count on it. De Blasio has the naivete of John Lindsay and the arrogance of Rudy Giuliani. And Lynch? He faces both contract negotiations and an upcoming union election.