Female Realtors are exercising caution in the wake of several recent incidents in the Fall River area where salespeople have received suspicious calls from a man, who says he wants to buy a home and then mentions going on a date with them, police said. The suspicious caller has called Realtors' cellphones as early as 6:20 a.m. and as late as 11:30 p.m. over the past two months; he calls them by their first name; refers to a past showing; and has occasionally mentioned taking the salesperson out on a date to Foxwoods, Fall River police said in an alert issued to Realtors.