RED BLUFF, Calif. -

New details have been released regarding the circumstances of 14-year-old Marysa Nichols' death. Her body was found behind Red Bluff High School on Feb. 28 after she had been missing for two days.

A returned search warrant and affidavit, made public Tuesday, show that when Nichols was found, she was laying face down and covered in a "foam object with shrubbery."

Police said the shrubbery appeared to have been pulled from nearby and placed on her head.

The affidavit mentioned that her pants were buttoned and did not appear to have been disturbed. Her chest was partially exposed.

Marysa Nichols: The Investigation Timeline

Nichols was found with a gray zippered sweatshirt near her head and her green sweatshirt at her feet.

The report said she had an injury on her right forearm and a facial injury. She also had a "yellow colored cloth type item" wrapped tightly around her neck.

This item, police suspect, is what may have been used to kill Nichols. The preliminary autopsy, which was released last week, said Nichols was strangled.