> Police are not asking for the entire search history of everyone in the town, then combing through it to see what they've searched for. Rather, police are asking Google who, in a narrow amount of time, searched for the name of a relatively unknown person who had $28K stolen from him.

Where would you draw the line?

Suppose they don't find what they're looking for in that request. Would you be okay with them expanding the time little by little? Perhaps adding other search terms? What about for other crimes? Other services (Facebook, Bing, Yahoo!, etc...)?

Wouldn't capable prosecutors for future cases simply use this as precedent and expand the parameters little by little?

There is no clear line to draw after you cross this line.