Some cops are wise to that and are using businesses to set traps. Take the general exchange number but do research on the Net concerning the company, how long it has been around, what it sells, ect,ect. Then ask a few selected questions of the gent based upon what has been learned from the Net research when the guy is reached thru the main exchange number. The scope of information that the Net provide can produce an endless supply of questions. The more exotic the questions that he can answer the more likely he is real.