A 14-year-old high school student in Steilacoom, Washington, carefully planned an attack targeting a girl at his school, according to charges. He's accused of luring the girl from a classroom, then hitting her repeatedly in the head with a hammer in what prosecutors call a "long thought out and prepared plan."

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A probable cause affidavit filed in Pierce County Juvenile Court states on Tuesday, the teenager used duct tape to keep locks from engaging on doors to the school's auditorium, then lured the girl into the room by bringing a note to her class claiming she needed to go to a counselor's office.

He also allegedly admitted to planning to kidnap the girl, saying, “He wanted to knock her out so that he could rape her and was surprised that she was still conscious” after using the hammer to hit her repeatedly in the head.

Steilacoom police said they found duct tape, which the teenager admitted he was planning to use to bind the girl's hands after the assault. The attack only stopped when the girl begged him not to kill her, according to the affidavit.

Although he faces charges of attempted first-degree murder, assault and kidnapping with sexual motivation, prosecutors say because of a new state law, he cannot be charged as an adult. KIRO-TV did not release the suspect's name because of his age.