The two girls, ages 11 and 12, attend Elk Plain School of Choice in Spanaway.
Beth Smith, the mother of the girl targeted in the video, reported it to the Pierce County Sheriff’s Department on May 6, sheriff’s spokesman Ed Troyer said.
The cartoon video, titled “Top Six Ways to Kill Piper,” showed several ways to kill Smith’s daughter, including poisoning and shooting. Piper also attends Elk Plain School of Choice, which is in the Bethel School District.
A search of YouTube on Friday did not show the video active on the popular video-sharing Web site.
Troyer said there won’t be criminal charges filed against the girls who made the video.
“We just don’t believe it was done with any malice or hate,” Troyer said, adding that the girls called the victim’s mother crying and upset after the incident.
School district officials said they have disciplined three girls in connection with the video. They can’t reveal exactly what measures they took because of laws protecting student privacy, district spokeswoman Krista Carlson said.
“We think appropriate discipline was administered,” she said.
The Associated Press contributed to this report.