This girl never worked for the government and had a little boy who was turning 4 in a couple of months when she died. I don't think she would have given him up to testify against whoever she was getting her drugs from. My guess is that they knew that she'd been beat up and that she was on a lot of drugs and were having a hard time determining what the cause of her death was?
I dunno, the detective in charge of the investigation sent flowers to her family. Would they have done that if she had just simply overdoesed?