Criminal law is governed by an interesting mix of constitutional, statutory, and case law on both the federal and state levels. Additionally, there may be administrative regulations that are relevant in a given situation. The following checklist can be a good starting point:
Title 18 of the United States Code covers federal crimes and criminal procedure, but criminal provisions can be found throughout the U.S. Code.
Part 4 of the General Laws of Massachusetts (Chapters 263-280) covers crimes, punishments and proceedings in criminal cases. Other important chapters of the General Laws include Chapter 90 (motor vehicle offenses) and Chapter 94C (controlled substances).
Browse the table of contents and indexes for state codes to find relevant titles/chapters.
Secondary sources such as treatises can lead you to pertinent cases on your topic, as can an annotated statutory code. Also, try researching cases by topic on Westlaw and LexisNexis.