[VIDEOS AND PHOTOS BY HILLEL ENGEL, PHOTODYNAMICS, & JDN IN EXTENDED ARTICLE]

Police officers from around the U.S. joined grieving family members as they mourned a 32-year-old immigrant who realized his dream of being an NYPD officer but was gunned down in his squad car.

New York City Mayor Bill de Blasio and Police Commissioner William Bratton eulogized Officer Wenjian Liu on Sunday as an incarnation of the American dream: a man who had emigrated from China at age 12 and devoted himself to helping others in his adopted country.

But thousands of officers turned their backs as de Blasio spoke, repeating a stinging display of scorn for a mayor who many officers say is anti-police.

The gesture among officers watching the mayor’s speech on a screen outside a Brooklyn funeral home added to tensions between de Blasio and rank-and-file police even as he sought to mollify them.

“Let us move forward by strengthening the bonds that unite us, and let us work together to attain peace,” de Blasio said.

Liu had served as a policeman for seven years and was married just two months when he was killed with his partner, Officer Rafael Ramos, on Dec. 20.

Liu’s weeping, father, Wei Tang Liu, said that his only child used to call after every shift to say: “I’m coming home today. You can stop worrying now.”

Dignitaries including FBI Director James Comey and members of Congress joined police officers and other mourners at a service that blended police tradition with references to Buddha’s teachings.

“When one of us loses our lives, we have to come together,” said Officer Lucas Grant of the Richmond County Sheriff’s Office in Augusta, Georgia.

After hundreds of officers turned their backs to a screen where de Blasio’s remarks played during Ramos’ funeral last week, Bratton sent a memo urging respect, declaring “a hero’s funeral is about grieving, not grievance.”

But some officers and police retirees said they still felt compelled to spurn the mayor. Police union leaders have said he contributed to an environment that allowed the officers’ slayings by supporting protests following the police killings of Eric Garner on Staten Island and Michael Brown in Ferguson, Missouri.

“The mayor has no respect for us. Why should we have respect for him?” said retired New York Police Department Detective Camille Sanfilippo, who was among those who turned their backs Sunday.

The officers’ killer, Ismaaiyl Brinsley, committed suicide shortly after the brazen daytime ambush on a Brooklyn street. Investigators say Brinsley was an emotionally disturbed loner who had made references online to the killings this summer of unarmed black men at the hands of white police officers, vowing to put “wings on pigs” in retaliation. He started his rampage by shooting and wounding an ex-girlfriend in Baltimore.

The deaths strained an already tense relationship between city police unions and de Blasio. Patrolmen’s Benevolent Association President Patrick Lynch, whose rank-and-file union is negotiating a contract with the city, turned his back on the mayor at a hospital the day of the killings and said de Blasio had “blood on his hands.”

After Sunday’s show of disdain, Lynch said officers “have a right to have our opinion heard, like everyone else that protests out in the city” and noted that officers’ “organic gesture” was outside the service. The mayor got a respectful reception among police officials inside.

The NYPD declined to comment, and de Blasio spokesman Phil Walzak said the mayor was focused on honoring the fallen officers.

George Breedy, a lieutenant with the St. Charles Parish Sheriff’s Department in Louisiana, said he wouldn’t protest de Blasio. “We’re here to pay respect to the officers,” Breedy said.

Liu’s funeral arrangements were delayed so relatives from China could travel to New York, where he married Pei Xia Chen this fall.

“He is my soul mate,” she said. “My hero.”

(AP)