A family-run, Panama-based company with an office in Coral Gables, Fla., has sued a former bank subsidiary of American Express and a so-called feeder fund to Bernard Madoff’s investment group. The suit alleges the bank, the fund and others caused $10.6 million in losses by ignoring the warning signs of a Ponzi scheme.

“This is a case about the defendants failing to do what they were supposed to do. Had they done their jobs, millions of dollars would not have been lost,” said attorney Jorge Mestre, partner with Rivero Mestre & Castro in Miami. Mestre represents the plaintiff, Headway Investment Corp., which owned shares in Madoff-related funds worth around $10.6 million, according to the complaint, which was filed in Miami-Dade Circuit Court.