The victim, also 12, was stabbed in the legs, arms and torso in Saturday's attack but survived despite having major organs injured, crawling out of the woods before being found by a bicyclist, authorities said. She underwent surgery in a local hospital and is in stable condition, police said.
The two alleged attackers were charged with attempted first-degree intentional homicide in a criminal complaint filed in Waukesha County Circuit Court, being accused of attacking their classmate in a park in Waukesha, 20 miles (32 km) west of Milwaukee.
A five-inch (13 cm) knife was found in a backpack of one of the girls after they were taken into custody on the day of the attack, authorities said.
According to the criminal complaint, one of the girls was fascinated by a character on a website about horror and nightmares and was inspired to kill someone, convincing the other girl to take part in the crime, the complaint said.
After a sleep-over on Friday night, all three girls went to play on Saturday in the park and the two girls attacked their classmate, the complaint said. One girl held the victim down and stabbed her 19 times, according to the complaint and police.
"Incredibly and thankfully, the victim survived this brutal assault," Waukesha Police Chief Russell Jack told a news conference.
Bond was set at $500,000 for each of the girls, according to court records.
Attorneys for the two accused girls could not be reached for comment.
© Thomson Reuters 2014