Two American 12-year-olds have apologised for stabbing their friend and called it "wrong," police said.
The New York Daily News reported the two girls from Wisconsin allegedly stabbed their classmate 19 times Saturday in an act of allegiance to Slenderman, a fictional character they read about online.
NBC reported the two girls told police they struggled to decide who would be the one to wield the knife.
Morgan Geyser and Anissa Weier invited their victim to a sleepover on Friday night. When the three girls played hide-and-go-seek the next morning in a park, Geyser and Weier attacked, police said.
But the two handed the knife back and forth while arguing who should stab the girl and who should hold her down.
Ahead of the attack, Geyser had a "nervous breakdown," and Weier said she was too squeamish to go through with the plan, they told police.
The victim was in stable condition Monday. Geyser and Weier have been charged with attempted murder.
The two girls were charged as adults with attempted first-degree murder Monday. If convicted, they could face up to 65 years in prison.