For two years, the two sons of jailed financier Bernard Madoff portrayed themselves as honest whistleblowers of their father's historic fraud. A court-appointed trustee depicted them as bungling money managers who did nothing to protect investors.

The suicide of Mark Madoff leaves unanswered questions for investors seeking payback for the billions of dollars his father siphoned — and for criminal investigators who continued to pursue charging Madoff's family for knowing participation in the fraud.

The 46-year-old Madoff — Bernard Madoff's eldest son — hanged himself Saturday by a dog leash on a metal ceiling beam in his Manhattan loft apartment, his 2-year-old son asleep in another room. The death was officially ruled a suicide by hanging Sunday by the city medical examiner.

He died on the anniversary of his father's arrest two years ago in the largest Ponzi scheme ever recorded. It followed the filing in recent weeks of dozens of lawsuits by trustee Irving Picard as he pursued billions of dollars in damages against those who profited from the multi-decade fraud.

Increasingly, Picard has stepped up his language in lawsuits against those who knew Madoff well, describing an Austrian banker accused in a lawsuit Friday of being Madoff's "criminal soul mate" in her efforts on behalf of Madoff's fraud.

Last Wednesday, he included the brothers as defendants in an $80 million lawsuit he brought against the London-based international arm of Madoff's business, saying the overseas operation was used to siphon off money from the fraud for the Madoff family.