Well, theoretically they can. And that's why the FBI started the VICAP program, where jurisdictions submit unsolved violent crimes to a central database so that connections can be made. The problem is egos and beaurocracies (sp). I've read too many true crime books where different jurisdictions refused to work together because one or the other wanted the credit for catching the bad guy, or they didn't think the crimes were connected. Also, if you've ever worked on a committee, you know how much of a pain it can be to get any group of people to work together on anything. Since each district, city, county, state and the FBI work completely independently under normal circumstances, you can imagine how difficult it is for them to coordinate.