Shadows of the Past

Dear Journal,

I am a DNA analyst, so a few days ago, I went to 711 just for a few minutes to buy some hand sanitizer to help avoid tampering with evidence. Then, the guy in front of me stole a water bottle and threatened the cashier with a gun, before the police came and arrested him a few minutes later! 3 days after that, I found a threatening message written on my bedroom wall. The message said, "You seem so happy. Too bad that won't last long." Upon further research, I found out this message was written in the blood of all the workers, the police, other customers, and robber I had encountered in 711 that day! Who did this? Why? What do they want? Are these people still alive? What happened between them all? Why was I allowed to live? How does this person or multiple people know where I live? What relationship do they all have, and if they have any relationship whatsoever, why did they act like they had never met each other? Both the recent events and the uncertainty terrify me to no end...

I am purposely not including my name on this out of fear and desperation...