It is poorly written in terms of language and and handwriting which means that they were most likely uneducated. They were also left handed making it hard to kill the victims (all victims were killed left to right with a knife). There are some factors to point towards it being real like the fact a kidney was missing and now the police receive one that has be preserved in ethanol although by the time this was written, you can presume that the news about the death was already out.