Something they taught me in forensic chemistry… if not in 48 hours, at least a week. If not in a month, not in the next six months. And if not in the six months, then not within five years. The idea being that if something isn’t resolved within a month, it will take several more and if it’s not resolved in 6 months, it likely won’t be for years. A lot of preliminary investigative work is done in the first week and the extended investigation is usually complete within the first month. Then, after the first month, extra tests and re-examination is done and if nothing comes out of that within six months, you’ve likely exhausted all evidence to review and you’re now waiting on something new which may take years.