A pair of pit bulls attacked and killed a 7-year-old boy in Lowell, Massachusetts.
A preliminary investigation suggested the unidentified boy entered a fenced area containing the two pit bulls, which then attacked him, the Middlesex district attorney's office said in a statement to several local media outlets.
Neighbors witnessed the attack at around 6 p.m. Saturday evening and frantically began calling police.
"I heard someone yelling, 'It's my baby! It's my baby!' and I come to find out that it was my daughter's friend's son," neighbor Annmarie Dizazzo told WFXT.
Records show there were multiple 911 calls.
"A child's being attacked by some sort of animal," the operator told police. "Apparently the dog will not let go of the child."
When police arrived, the child was already dead, Fox News reported. By then, at least one of the dogs had escaped the enclosure.
It then charged at a police officer, who shot the dog, which continued running toward him anyway.
"Lowell, shots fired, the dog is hit, it's still coming at me," the officer told the operator.
That pit bull was later captured and euthanized. The other dog is currently being held by animal control officials, according to the Boston Globe. The incident remains under investigation, and no charges have been filed.
One neighbor told WHDH that the boy's mother is "trying to wake up from this nightmare."
The Lowell City Council passed an ordinance in June 2011 that limits pet owners to two pit bulls, which must be spayed or neutered. Owners also have to keep the dogs muzzled or secured in a temporary enclosure, according to the Lowell Sun.
Many who perceived the dogs as dangerous argue that they shouldn't be allowed as pets - and in many cities, they're not. They're also banned from all military bases in the United States for being a "dangerous dog breed."
From 2005 to 2015, pit bull attacks caused 232 deaths, which accounted for 64 percent of all deaths caused by dog bites during that decade, according to the nonprofit organization DogsBite.
But some argue that the dogs themselves aren't inherently dangerous. The breed descended from the English bull-baiting dog, an animal that was bred "to bite and hold bulls, bears and other large animals around the face and head," according to the American Society for the Prevention of Cruelty to Animals.
Eventually, people began pitting the dogs against each other, once baiting large animals was outlawed in the 1800s. Through crossbreeding with terriers, the American pit bull was created.
But the ASPCA argued that while pit bulls "may be more likely than other breeds to fight with dogs," this doesn't translate into aggression toward humans.