NEW YORK – One was Bernard Madoff’s right-hand man for decades. Two others were executives in his firm. All are family — and presumed targets of the investigation of Madoff’s epic fraud.

But nearly three years into the probe, Madoff’s brother, son and niece have avoided criminal charges, raising the possibility that they could get off entirely.

People with knowledge of the case say federal investigators turned over potential criminal evidence against Peter, Andrew and Shana Madoff to prosecutors in the spring with expectations that a decision on whether to prosecute them would be made by the end of summer.

The U.S. attorney’s office in Manhattan hasn’t taken any action, suggesting any potential criminal evidence isn’t strong enough to conclusively prove that the three knew that Madoff spent decades orchestrating the largest Ponzi scheme in history, said the people, who spoke on condition of anonymity because a final decision hasn’t been announced. All three family members have denied any wrongdoing.

Prosecutors already had decided not to charge Madoff’s wife, Ruth. His son Mark, another former executive who was under scrutiny, committed suicide last year.

The FBI’s New York City office on Friday called the probe “an open and active investigation,” but it declined to comment further. The federal prosecutor’s office declined to comment.