Police found the victim with a critical wound on the right side of her head at around 11 a.m. on Wednesday, at the property on the 2300 block of North Bouvier Street.

She was left unattended at the time of the incident, with two other children aged 5 and 12. The 12-year-old alerted law enforcement after the shooting, police said.

The girl was taken to Temple University Hospital, but was pronounced dead at 1.50 p.m.

Police recovered two guns from the property. “There were multiple weapons located within the residence and, at this time, we don’t know the legality of those weapons,” Philadelphia Police Cpl. Jasmine Reilly said.

Officials did not provide anymore information around the shooting, including how or if the children were related. Newsweek has contacted Philadelphia Police for comment.

However, Patrick Flood, a family friend who lives nearby, told the Philadelphia Inquirer that the 9-year-old girl was the cousin of the 5-year-old shooter. He said the 12-year-old was the victim’s brother.

Speaking to reporters at the scene, Philadelphia District Attorney Larry Krasner said the city had to do more to protect children from gun-violence.

He said the shooting was “heartbreaking” and that Philadelphia had “too many guns, and they’re not secured safely when they’re out there.”

“We’ve had enough. We have to come together as a community. We have to come together as criminal justice partners. We have to come together, with all the institutions and all the organizations and do better,” Krasner said. “This is unacceptable.”

Rhonda Wilson, 53, who lives at the house next door to the shooting, told the Inquirer that her neighbors’ children do not go out much and that their father was “always out in the street.”

“I’m just surprised that they left them by themselves,” Wilson said. “These are your kids. I mean, what is so important that you would leave your kids in a house by themselves?”

So far in the eastern American city in 2021, 27 people have died from homicides, according to data from the Philadelphia Police Department.

On Tuesday, one man was arrested in connection with the shooting of a 25-year-old man who was gunned down in while walking his dog in the city. Philadelphia Police said a second suspect has also been identified.

The victim, Milan Loncar, was walking his dog January 13 when two men wearing dark-colored clothing and masks approached him. He was then shot in the upper chest before the two suspects fled, police said.

Some 449 people died of homicides in Philadelphia last year, an increase from 143 from 2019, where 356 died.