Yup. Kinda like when my 7-year-old tested positive for meth, and I filed a police report which included his test, my ex's 4 positives, and other evidence... and the "detective" did nothing more than call him down to the police station for an interview. The case was summarily dropped due to "lack of evidence" (lack of investigation, if you ask me).
It irks me to no end that they'll actually prosecute things like speeding tickets, but anything that happens to private citizens, they just don't seem to care. It seems only crimes that were directly witnessed by police officers stand a chance.
It's a mess. Sorry you're going through this.