bloodshed was planned for today at this middle school in los angeles, county. a mass shooting plot foiled after a 13-year-old student with access to this weapon allegedly threatened to open fire on classmates before deputies made a chilling discovet hime >> we recovered that firearm and some other things that are important part of our investigation. >> reporter: after officers obtained a search warrant, investigators say they recovered an a.r. 15 rifle, a high capacity magazine, 100 rounds of ammunition, a list of intended victims and a drawing of the school layout. >> never thought it could happen here. that's terrifying. >> reporter: multiple students overheard the threat on campus and teachers emailed administration about concerns raised by the students. >> reporter: with the 13-year-old boy taken into custody for making criminal