From the moment the news broke of a mass shooting on Park Avenue on Monday, misinformation careened through social media, declaring the massacre an act of Islamic terrorism or blaming Zohran Mamdani, who is seeking to become the city’s first Muslim mayor.
Mr. Mamdani’s surprise victory in the Democratic primary last month, coming from the far left, stirred up anti-Muslim animus not just in New York but also in pockets nationwide.
The right-wing agitator Laura Loomer, who has promoted numerous conspiracy theories — and who has become a confidante of President Trump — led the charge in blaming Mr. Mamdani for the attack, in which a gunman killed a police officer and three other people before shooting himself. “The cop killer in NYC who just killed an NYPD officer was a Mamdani supporter,” she posted on X, adding, “@ZohranKMamdani is inspiring a generation of pro-Islamic cop killers. This is why you don’t elect Muslim immigrants to office.”
Contributing to the confusion, especially in those first hours after the shooting, when details were scarce, was the name of one of the victims: Didarul Islam, a New York police officer and Bangladeshi immigrant who was working off-duty as a security guard.
Officer Islam, 36, was a father of two, with a third child on the way; a mentor to other Bangladeshi immigrants; and an active member of his mosque. Police Commissioner Jessica Tisch lauded his service to the city. “He made the ultimate sacrifice, shot in cold blood, wearing a uniform that stood for the promise that he made to this city,” she said. “He died as he lived: a hero.”
Around his home in the Parkchester section of the Bronx, members of the Bangladeshi community gathered Monday night to show support and grief for his family, and played down the anti-Muslim comments beginning to circulate, said Nurul Islam, a friend of Officer Islam’s and secretary of the American Bangladeshi Welfare Organization in the Bronx. “The killer is the killer,” Mr. Islam said. “He doesn’t care who is Muslim, who is non-Muslim.”
Other conservative commentators sought to tie the shooting to Mr. Mamdani without mentioning his religion or ethnicity, recalling past statements, which he has since disavowed, in which he called for defunding the police.
“REMINDER: Communist Zohran Mamdani wants to defund the police,” the conservative podcaster Benny Johnson posted on X. “No cops rushing in — just social workers trying to reason with gunmen. New York, wake up.”
Mr. Mamdani, a democratic socialist who as a mayoral candidate has adopted a more accommodating stance toward the police, responded to the massacre during a visit to Uganda, where he grew up.
“I’m heartbroken to learn of the horrific shooting in midtown and I am holding the victims, their families, and the NYPD officer in critical condition in my thoughts,” he tweeted. “Grateful for all of our first responders on the ground.”
Shahana Hanif, a Democratic City Council member and supporter of Mr. Mamdani who is also Muslim and Bangladeshi American, criticized what she called “the disinformation spreading online that incoherently blames last night’s tragedy on Muslims and our Democratic nominee for mayor, Zohran Mamdani.” She added: “This bigoted rhetoric dishonors the lives we lost and endangers our Muslim communities as we mourn the four victims, including Officer Islam, a Bangladeshi Muslim who died protecting others.”
On social media, unfounded reports proliferated, possibly stemming from a pro-Palestinian demonstration near the Park Avenue building, that the shooter had yelled “Free Palestine.” As details gradually emerged about the shooting, the false posts had a momentum of their own, with some accusing mainstream news outlets of refusing to report the supposed shouts of “Free Palestine.”
In response, the Council on American-Islamic Relations, the country’s largest Muslim civil rights organization, denounced “those anti-Muslim bigots and anti-Palestinian racists who gleefully rushed to blame yesterday’s mass shooting on Muslims and Palestinians without any evidence,” condemning the “blind hatred that would lead someone to respond to tragedies like this shooting with such racism and bigotry.”
Wesley Parnell contributed reporting.