Prosecutors revealed in a new court filing that Bryan Kohberger purchased a balaclava months before the murders of four University of Idaho students. The surviving roommate who saw the murder suspect leave the home that night sketched that man in a mask similar to a balaclava.

New filings from prosecutors detail a paper they hope to introduce into evidence -- pointing out similarities between Kobherger's writings and the murders -- while also making new claims about the purchase of a mask.