Hassy_101
Okay.. So many things... First off, the doctor who would have done the autopsy would have been a government worker since this was a homicide and there definitely would have been an autopsy. Your GP can only sign a death certificate if you died of natural causes or in a hospital. Secondly, didn't they say there was a body? So he wasn't cremated and you could still do an autopsy now to determine cause of death. Testimony alone from an eye witness in this case is not thorough. It's sloppy and it's not how things are done. Finally, most people don't have a funeral so quickly. How long after he died is this? That's just the obvious things to me. The plot doesn't hold water.
I'm sorry I don't find this plausible. What about the detectives that were assigned the case? Were they bribed too? You would have had to stage a crime scene. Show injuries. The black blood would be a red herring for any detective. Respectfully I think I will stop here. I wish you luck in the future