A grandson calls and says he’s in trouble — what do you do? The male caller identifies himself as a grandson, who said he was in jail in Canada and needed money for bail. Variations on the theme include car or other legal troubles in Canada, saying that authorities won’t let them leave the country without the money. The caller asks that money be sent to a friend, through Western Union. While there is little police can do to help those who have lost money to such crooks, police warn others to be wary of such scams. Investigators say such scams have been used increasingly to target elderly people, by researching their would-be victims’ personal information before making contact. A Web site, phonebusters.com, which was set up by a Canadian law enforcement task force, contains a long list of such scams. The Canadian scam task force can be reached by phone at 1-888-495-8501.