There are means to track people open to law enforcement, but not to the public. There is an internship once you're in college, some local police departments have explorer clubs. I've got crooks to catch. There has to be a LOT of evidence before we get a search warrant we can't just barge in to your house and take whatever we want. That's the 4th amendment to the constitution.
Hackers leave electronic fingerprints like bank robbers leave real fingerprints.
One time we found the person while they were still online hacking the box. Yes cool, but we mean that computers attach numbers to everything.