Grieving relatives and outraged community members are demanding answers and accountability in the fatal police shooting of a 13-year-old boy with an air gun as he was being held on the ground by a cop in upstate New York.

In a message posted on the GoFundMe website, victim Nyah Mway's sister said he was a "good kid" who'd "never gotten in trouble with law enforcement before" the deadly encounter in Utica.

Thoung Oo said body camera recordings released by the city's police department, witness accounts and the official version of events "don't add up, especially when they told my parents (who don't speak English at all) that there was a shoot out."

"We need answers," she wrote Sunday. "In the body cam, we could hear an officer saying, 'Why did he shoot?'"

Tensions also boiled over during a Sunday meeting involving city Mayor Michael Galime and more than 100 members of Utica's Karen community, which comprises about 15,000 refugees from Myanmar who speak the Karen language.

Although the 2 1/2-hour meeting in a local church was mostly peaceful, organizers had to intervene and calm several people after an outraged woman began shouting at Galime, according to the New York Times.

A video clip posted online Monday by NBC's "Today" also showed a young woman saying, "The boy was already on the ground. He was shot. Why shoot him when he was already held down on the ground?"

One of Nyah's cousins, Isabella Moo, told the Associated Press that the killing "should not have happened, and our police officers need to be trained a lot better or a lot differently."

"The city needs to be held accountable, and this should not have been done to any child," Moo said.

Another cousin, Lay Htoo, told AP that Nyah's parents want the officers involved "to be in prison forever."

Police have said the incident unfolded late Friday after Nyah and another 13-year-old were stopped because they fit the descriptions of suspects in a Thursday armed robbery nearby.

Body camera video released Saturday showed that after an officer said he needed to pat them down for weapons, Nyah ran away and appeared to point a black object, according to AP.

The cops thought was it was a handgun, police said, but it but turned out to be a BB or pellet gun that didn't have an orange band on the barrel that's often used to distinguish such items from firearms.

Officer Bryce Patterson caught up with Nyah, tackled and punched him, and as the two wrestled on the ground, Officer Patrick Husnay opened fire, AP said, citing body camera video.

A single shot hit the teen in the chest and killed him, police said.

On Sunday, state Attorney General Letitia James said she'd launched an investigation pursuant to a state law that requires the attorney general to probe all deaths caused by law enforcement officers, whether on duty or not.