On the evening of June 4th, a few hundred protesters were marching through the South Bronx when they walked into an ambush. As heavily-armored NYPD officers on bikes blocked the group’s path, a second line of cops charged from behind just after 8 p.m., violently arresting more than 250 people — including legal observers and essential workers — in the NYPD’s most aggressive show of force against protesters since the citywide demonstrations began in May.

During his daily press briefing the next morning, Mayor Bill de Blasio dismissed accounts of police brutalizing peaceful demonstrators.

“I believe that you believe what you're saying,” he told Gothamist. “We had observers from City Hall who saw a very different reality.”

According to internal emails and interviews with six City Hall staffers, some of de Blasio’s own observers were trapped in the Mott Haven kettle. As officers clubbed and pepper-sprayed protesters and bystanders alike, the mayor’s closest aides were scrambling to rescue two employees with the Community Affairs Unit [CAU] from imminent danger.

“We have CAU folks in that intersection in Bronx and it is not good and [the NYPD] is not letting them get out of the situation," Natalie Grybauskas, the mayor’s senior policy advisor for emergency management, wrote to her colleagues at 8:19 p.m.

At 8:25 p.m., America Canas, the head of the Mayor’s Office of Community Affairs Office, requested a medic be sent to the intersection, noting that one of her staff was still “behind the line.”

By that point, the NYPD had already arrested many of the volunteer medics at the scene. The staffers said they witnessed at least two people having a panic attack. Despite badges indicating they were “Mayor’s Liaisons,” the NYPD declined to let the City Hall staffers leave the narrow street for nearly 30 minutes.

One of many medics arrested by police in Mott Haven shortly after curfew on June 4th

The emails were shared with dozens of high-level City Hall staffers, including First Deputy Mayor Dean Fuleihan and Deputy Mayor Emma Wolfe, who is also de Blasio’s chief of staff.

It’s unclear whether the mayor had spoken to his own Community Affairs staffers when he praised the NYPD for “effectively” handling the situation, and falsely claimed that protesters were given the opportunity to disperse before the 8 p.m. curfew.

In a statement to Gothamist on Wednesday, de Blasio’s press secretary, Freddi Goldstein, said the mayor’s narrative was based on “a different City Hall staffer,” who attended the protest but did not witness any violence and was not personally kettled. The Mayor’s Office declined to make that person available for an interview. None of the city employees were injured at the scene, the spokesperson said.

Several City Hall staffers, who spoke to Gothamist on the condition of anonymity for fear of losing their jobs, were disturbed by their boss’s strident defense of the NYPD.

The incident, according to one source, proved de Blasio “doesn’t represent the public servants who work for him.”

While the Mott Haven episode was the most glaring example, staffers said de Blasio had adamantly refused to hear evidence of NYPD brutality from the outset of the protests — even when those accounts were relayed by members of his own administration.

“He had a narrative that he wanted to tell himself and the world,” said one City Hall source. “He would only digest the information if it fit that narrative.”

Another source close to de Blasio described “consistent problems where the mayor was getting information from primarily [the NYPD] and drowning out other voices.” When his own staffers shared videos or accounts of unprovoked police brutality, de Blasio would immediately call Police Commissioner Dermot Shea, who’d reassure him that the force was justified, the source said. “Everything had an explanation.”

In many cases, the NYPD’s description of events has proven false. Following the Mott Haven arrests, Shea said the aggressive crackdown was justified because participants were caught “bringing a gun and gasoline and weapons to the scene.”

That gun was recovered from an alleged gang member, several blocks from the protest and hours before it began. Police later acknowledged that no gasoline was ever seized. Two others in the area charged with possession of burglar’s tools, after cops found a sledgehammer, screwdrivers and a lug wrench in their pickup truck, according to the Bronx District Attorney's Office.

While Shea described the protesters as “outside agitators” looking to “cause mayhem,” the march was led by veteran Bronx organizers and attended by many local residents.

One of those participants was Chantel Johnson, a South Bronx school teacher. During the State Attorney General’s hearing on police brutality, she testified that cops hit her in the face with a baton. She said she texted her mom at 8:05 p.m. because she feared she wouldn’t make it out alive, and recalled watching cops beat protesters so bad that their bones cracked.

"How do I explain [to my students] that we were peaceful and we were abused and attacked?" she asked. "How can I explain that? I can't justify that behavior."

A spokesperson for the Mayor’s Office said the incident was under investigation.