The officer, Peter Liang
, 28, was found guilty of manslaughter and official misconduct earlier this month in the shooting death of Akai Gurley, 28. He was immediately fired after the highly unusual conviction of a cop for the shooting death of a civilian. He faces a sentence of up to 15 years.
A group calling itself the Coalition of Justice for Liang on Saturday staged rallies from Boston to Los Angeles, with supporters claiming the officer was subjected to "selective prosecution." The group said about 100,000 people took part in 30 cities.
Protesters carried signs with messages such as "Justice not politics," "One Tragedy, Two Victims," and "Equal Justice, No scapegoating."
Liang, with 18 months on the job, was on patrol in the dark stairwell of a Brooklyn housing project in November 2014 when he fired his gun. The bullet ricocheted off a wall and struck Gurley in the chest. The victim later died at a hospital.
Prosecutors said Liang's actions were reckless, and that he was more concerned about his story than helping Gurley.
"There are no winners," Brooklyn District Attorney Kenneth Thompson said after the verdict. "I told his mother I'm sorry. This is a tragedy all over."
Thompson said the decision was not a verdict against all NYPD officers, but one who ignored his official training.
But Liang's supporters -- many of them, like him, Chinese-American -- believe the officer was singled out for prosecution.
"We believe that Mr. Liang has been sacrificed as a scapegoat in a highly politicized criminal justice system, resulting from recent intensifying police-community relations," coalition spokesman Jack Ouyang said in a statement.
Liang's trial garnered attention beyond New York because of the controversy over allegations that police are too quick to use lethal force
, sometimes against unarmed people. Outrage over police shootings or excessive force has spurred protest movements in major cities such as Chicago, Baltimore and New York.
In the most well-known cases -- the fatal shootings of Michael Brown in Ferguson, Missouri
, and Walter Scott in North Charleston, South Carolina
, and the death of Freddie Gray while in police custody in Baltimore
-- the victims were unarmed black men.
In a plaza near the Brooklyn courthouse where Liang was convicted, hundreds of demonstrators gathered on Saturday.
Scores turned out Saturday afternoon outside in Atlanta as well. Many held small American flags as they packed about 100 yards of sidewalk, several people deep, outside CNN's headquarters.
In San Francisco, protester Amy Matecki said, "Peter Liang's incident brought the Chinese community together. We want to speak up. One voice, united together. Life matters, justice for all. No scapegoat."
"He was singled out as a victim for some political reasons," said Min Yan, a physician in Oakland.
During closing arguments at Liang's trial, the officer's lawyer called the fatal shooting tragic but not a crime, stressing that Liang followed procedures. Police had described Gurley was "a total innocent."
"What happened here is a tragedy," defense attorney Rae Koshetz said. "It's a terrible tragedy, but it's not a crime."
Prosecutors argued that Liang showed poor judgment.
Liang took the stand at trial and lost his composure when asked to recount what happened in the stairwell that night
"I was panicking. I was in shock, in disbelief that someone was actually hit," he said.
Gurley's death occurred a few months after Eric Garner
died as police tried to arrest him on Staten Island. The chokehold death of Garner, an unarmed 43-year-old man, sparked street protests, a review of police procedures and calls for a federal civil rights investigation. A grand jury declined to prosecute the officer.