Attorney Dan McGuire has seen his fair share of scams aimed a law firms over the years, and he thinks he’s pretty good at recognizing them. But he said a new version of an old scheme was so sophisticated that he felt the need to call the FBI and wants to warn fellow lawyers.

“This is a real problem with attorneys,” said McGuire, whose Stamford and White Plains, N.Y., practice involves banking law and business litigation. “We have to alert the bar.”