New York City Mayor Bill de Blasio’s already strained relationship with the NYPD has suffered another setback with revelations of a top aide’s relationship to a convicted killer who has often mocked officers as “pigs.”

While critics rush to chastise the Mayor’s aide– the fact remains that recent months have revealed a disturbing trend of police violence and this aide isn’t involved in setting mayoral policy.

Recently, the mayor drew the NYPD’s ire when he sided with frequent critic Al Sharpton over the death of an unarmed suspect. Eric Garner was choked at the hand of an officer who remains on paid leave with no indictment.  Public awareness of police brutality and police killings of unarmed men and women has continued to increase since the untimely death of 18 year old unarmed teenager Mike Brown. Several similar cases have come to national prominence and reveal the strained relationship between officers and communities of color.

Police unions say it’s only the latest incident that shows the mayor’s lack of support for the NYPD. Some of de Blasio allies acknowledge the mayor could do a better job of leading the department he is simultaneously trying to reform.

Bill de Blasio was viewed suspiciously by police from the beginning with his push to end stop-and-frisk, a policy that allows officers to stop anyone they deem suspicious that in practice has disproportionately targeted residents of color.

He also drew their ire when he called a police official to inquire about the arrest of a political ally, who was later released. Police said the release had nothing to do with the mayor’s request but the unions said the call made it seem like de Blasio was undermining officers.

Mayoral aides strongly disputed any suggestion that de Blaiso’s leadership over the NYPD had been compromised.

“The mayor has nothing but the strongest support for the brave men and women of the NYPD,” said spokesman Phil Walzak, who noted crime continues to fall.

But experts said there are political risks for de Blasio if the complaints grow louder. The perception that City Hall and the police are not compatible does not sit well with voters. Yet similarly, neither does the perception of an out of control police force.