The shooting deaths of two New York City Police officers at the hands of a deranged man last Saturday has drawn an outpouring of grief for the victims and their families, but also a backlash against the growing national movement to reform police practices.

In particular, critics have pointed to chants made by a group caught on videotape marching through the streets of New York, chanting for violence to be directed against police; suggesting the larger protest movement is to blame for the deaths of officers Raphael Ramos and Wenjian Liu.

Those wishing to link the #BlackLivesMatter movement to the officers’ deaths point to the fact that Ismaael Brinsley, who allegedly shot the officers multiple times in their squad car before fleeing and turning the gun on himself, posted messages on social media before the incident indicating he was motivated by the deaths of unarmed black victims Eric Garner in New York and Michael Brown in Ferguson, Missouri at the hands of white police. But Brinsley’s family points to his long battle with mental illness and multiple run-ins with law enforcement. And his first shooting victim was not a police officer, but rather his former girlfriend, Shaneka Thompson, who Brinsley shot in the stomach inside her Maryland apartment before boarding a bus to New York.

Related: Brown, Garner cases ‘exploited’ in NYPD officer deaths

I covered one of the major protests – the “Millions March NYC” demonstration on December 13th, which drew at least 25,000 peaceful protesters to the streets of Manhattan.

At the march, which I chronicled on my Instagram page, I heard my share of tough chants against the NYPD, whose officers lined the parade route. The officers I saw were grim-faced, but silent and professional, as a seemingly endless sea of marchers – white, black, old, but mostly young – chanted things like:

“Whose streets? OUR streets!”

“No justice, no peace, no racist police!”

“How to you spell racist? N-Y-P-D!”

You can characterize those chants as harsh; even as painting an overly broad, negative picture of police. But they reflect the frustration of young activists and citizens less molded by the church-led activism of the 1960s and more driven by current passion. They speak to a raw anger at a system those activists want changed. But they can’t be called an endorsement for killing cops.

Herald Square. #MillionsMarchNYC A photo posted by Joy-Ann Reid (@joyannreid) on Dec 12, 2014 at 12:46pm PST

Another frequent chant: “What do we want? Justice! When do we want it? Now! … If we don’t get it, shut it down! If we don’t get it, shut it down!” Though at no time have organized demonstrations shut down anything other than roads and bridges; a tactic members of the police union have used themselves, including in September 1992, as masses of police officers shut down the Brooklyn Bridge to protest then mayor David Dinkins’ push to create a civilian review board.

The chant I didn’t hear on Dec. 13 was the one captured on a cell phone video and uttered by a small group numbering a few dozen, marching in a cluster behind a makeshift banner:

“What do we want? Dead cops! When do we want it? Now!”

The video of that particularly venal bromide was taken from a window high above Murray Hill, an upscale neighborhood in the middle part of Manhattan’s east side. It has been replayed and repeated over and over as part of the coverage of the tragic killing of officers Ramos and Liu, including on MSNBC.

Some are attributing the chant not just to organizers of the New York march but even to Rev. Al Sharpton, whose National Action Network had nothing to do with the New York march and held its own separate rally earlier that day in Washington, D.C. with the spouses and parents of Eric Garner, Michael Brown, Trayvon Martin, Amadou Diallo and others, and televised on CSPAN and MSNBC.

Related: Thousands protest against police killings nationwide

And yet, evidence shows the group that engaged in the death chant against police weren’t part of Millions March NYC. And if they did indeed march on Dec. 13, they did so long after the larger protest had moved downtown. They were not part of the main group.

For one thing, according to the video, which was posted to Youtube the same day as the protest, the “dead cops” chant took place after sunset. You can see from the video that city lights are already on. The group starts by chanting “hands up, shoot back,” before switching to the death chant, and then an unintelligible chant at the end of the approximately 2 minute clip.

A story posted by the New York NBC affiliate says the marchers were proceeding “down Fifth Avenue at 32nd Street” at 4:30 p.m. The Millions March NYC protest kicked off at 2 p.m. as thousands gathered in Washington Square Park near New York University on 5th Avenue and 8th Street. After turning west on 14th Street the march, which stretched across all lanes and down more than ten city blocks, proceeded up 6th Avenue as far as Herald Square (home to the famed Macy’s flagship store) at 32nd and Broadway. It then proceeded downtown on Broadway, to One Police Plaza.

By the time it reached Herald Square, which is on the west side of the city at least a mile from Murray Hill, it was still daylight. My photos from Herald Square are time stamped at around 3:30 p.m.

The official march ended at One Police Plaza at 6:30 p.m., when the march’s permit expired, a point reinforced by a tweet sent by the organizers at 7:26 p.m.

“Once the march reached 1 Police Plaza the march ended and there was a tweet that went out saying that anything that happens afterward was not organized by the MMNYC,” communications director Kate McNeely told me.

McNeely added that some fellow activists took offense to the tweet.

“We caught backlash for that tweet,” she said. “Because people felt we were separating ourselves from other protesters. Our clarification on Facebook made it clear that we support any non-violent direct action done by those who desire an end to systemic police abuse and violence disproportionately impacting black people.”

Millions March organizers told me they don’t know the identity of the group was that was caught on cellphone camera marching through Murray Hill chanting about “dead cops.” But in response to press inquiries in the wake of the two officers’ slaying, the group released the following statement:

“On behalf of the Millions March NYC, we express our deepest condolences to the families of the officers who were killed on Saturday. Our march last weekend was a peaceful outcry that senseless violence in our society is harmful to trust, community, and security. This tragedy is in no way connected to our march, or ongoing protests against police brutality, discrimination, and profiling – and we condemn, and are disappointed with any entity that would try to imply such connection. As New Yorkers, we will continue to march for a peaceful society, where trust between communities and law enforcement is finally achieved.”