Thank you for entrusting me with your question. I am not going to defend the law, but please allow me to explain it. For felony charges, law enforcement has up to no less than seven years to actually file the criminal
in court; in a few cases, such as for a murder charge, there is no limit to the amount of time that they have to file charges. If they are going to file, they usually do it within a few weeks because it is to their advantage to do so; they carry the burden of proving beyond a reasonable doubt that you are guilty, so the more time that passes the more likely it is that their evidence will be compromised (memories fade, witnesses move away or die, evidence disintegrates, etc.), but they can wait up to no less than seven years in all cases.
Again, it gives me no pleasure to announce this, but please keep in mind that the experts are not credited for unaccepted answers and even where I can not get you out of a bind, my hope is that you can at least feel confident in your knowledge of your rights so you can get the best legal outcome under the circumstances, whatever that outcome may be.
I understand that you may have follow-up questions. Let me know if further clarification is needed. Thank you.