can the cops trace blocked calls
Of course yes, cops can trace blocked calls. No doubt about that. But if you don't want to waste any time, you or the cop's, try http://www.usnumberinfo.com/ I found it across the web and it was really useful.
Yes, the cops can trace blocked calls. They must have a warrant or court order to legally trace a blocked call.
I don’t know, why don’t you ask them? Kidding aside, yes they could. But if I were you, I would go to websites like http://callnumbersearch.com This can provide you all the information you need.