A 12-year-old boy in New Jersey accidentally shot his 9-year-old sister Saturday afternoon while the siblings were playing with a handgun, police said.
The young girl is in critical, but stable, condition at University Hospital in Newark, said Sgt. Ronald Glover, a city police spokesman.
Officers responded to reports of a shooting at about 12:18 p.m. on Renner Avenue in Newark; the girl had been shot in the chest, Glover said.
The 9-millimeter handgun was recovered at the home.
Glover said it was not immediately clear whether the children were home alone or who the gun belonged to, but a law enforcement official told the Los Angeles Times that the weapon may have belonged to the victim's mother's boyfriend.
Glover said it had been left unsecured.
At 7 p.m. Eastern Time, Glover said the victim's mother, 33-year-old Catrease Thomas, had been arrested and charged with endangering the welfare of a child and weapons possesion.
Police were still searching for the mother's boyfriend on Saturday night, a source told The Times.
"The City, the Police Department, the residents, we are all outraged that this senseless shooting has occurred, an incident that could have easily been avoided but for the carelessness of two adults. We have a 9-year-old clinging to her life as a result of that carelessness," Newark Police Director Eugene Venable said in a statement.
It's the latest episode of accidental gun violence linked to children in recent months.
In August, a 9-year-old from New Jersey accidentally shot and killed a shooting range instructor in Arizona when she lost control of the weapon she was firing.
Weeks earlier, a 5-year-old in Pueblo, Colo., accidentally shot a 3-year-old while the two were playing with an unattended weapon.
In April 2013, a 4-year-old Toms River, N.J., boy accidentally shot and killed a 6-year-old friend with an unsecured .22 caliber rifle. Police said the boys were playing "pretend shooting."