Damnit this is creepy

FAN THEORY BELOW, DO NOT READ UNTIL YOU'VE WATCHED THE VID (no the theory isn't mine, someone named Drink Me with a pic of bleach posted it)

  EXPLAINED: The weird thing Johnny at school was that he came out to say he loved David (hence having the same jacket). David said he was straight and had feelings for Annie. Johnny decided to get her out the picture and kill her. In the garden, he dug a grave for her using his bare hands. Once he finished digging the grave he ran to her house, broke in and took the knife from her and killed her with it. The last few messages was sent from Johnny to David, basically its "She can't have him if I can't"