Pierce County prosecutors released new details Thursday about what may have transpired in the minutes after the murder of a 15-year-old Tacoma teen found dead in a recycling bin.

Prosecutors are now pushing to charge Cristobal Arroyo, 14, with first degree murder as an adult in the case. His brother, Luis Arroyo, 16, will also be charged as an adult.

Both teens are accused of stabbing and killing Hector Hernandez-Valdez, 15, at their Tacoma home in June.

According to prosecutors, police found a note, believed to have been written by Cristobal, inside the Arroyo house that read, lay out bags, shut her up, hammer her bones, cutting off limbs, cutting off head, cutting open, and done.

It's not known who the female referenced in the note may have been. Police said Arroyo's mother came home to find the murder scene and was the one who notified authorities. A 7-year-old girl was also home at the time of the incident. She told detectives she saw a knife, and blood on the carpet. Prosecutors said the boys told her it was fake and ordered her to watch TV.

Another note, believed to have been written by Luis, read, cut open, shank the stomach, wack (sic) the head, camera set up.

Detectives recovered a cell phone video that purportedly shows Hernandez-Valdez face down in the Arroyo's bath tub as Luis andCristobal taunt and swear. The brothers told police during interviews they believed Hernandez-Valdez was alive at the time, prosecutors said.

Hernandez-Valdez was stabbed 34 times and his throat was slit.

A hearing on September 12 will determine whether Cristobal will be charged as an adult.

Information compiled by KING5's Lindsay Chamberlain

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