NEW YORK - Disgraced financier Bernard Madoff's eldest son hanged himself with a dog leash in his apartment Saturday, two years after his father's arrest in a multibillion-dollar Ponzi scheme that swindled thousands of investors of their life savings.

Mark Madoff, 46, was found hanging from a ceiling pipe in the living room of his SoHo loft as his 2-year-old son slept in a nearby bedroom, two law enforcement officials told the Associated Press.

Madoff, who had reported his father to authorities, was not criminally charged in the biggest investment fraud in U.S. history. He maintained that he and his brother, Andrew, did not know of their father's crimes until just before they turned him in. A law enforcement official said Mark Madoff was not facing imminent arrest and had not spoken to investigators pursuing possible charges in more than a year.

But he and other Madoff relatives have remained under investigation and have been named in multiple investor lawsuits accusing them of profiting from the scheme.

"This is a terrible and unnecessary tragedy," Mark Madoff's attorney, Martin Flumenbaum, said in a written statement. "Mark was an innocent victim of his father's monstrous crime who succumbed to two years of unrelenting pressure from false accusations and innuendo."

Madoff's body was discovered after his wife, Stephanie, became concerned when he sent an e-mail to her early Saturday that someone should check on their toddler son, the law enforcement officials said on condition of anonymity because they were not authorized to speak publicly about the death.

Madoff's wife, who was at Walt Disney World in Florida with her 4-year-old daughter, sent her stepfather to the apartment. The toddler was found unharmed, along with a dog.

Bernard Madoff, 72, swindled a long list of investors out of billions of dollars. He admitted that he ran his scheme for at least two decades, cheating thousands of individuals, charities, celebrities, and institutional investors. Losses are estimated at $20 billion, making it the biggest investment fraud in U.S. history.

He was arrested on Dec. 11, 2008, after confessing to his sons.

The scandal put a harsh light on members of the family. The financier's brother, Peter, played a prominent role in the family's company. Mark and Andrew Madoff worked on a trading desk at the firm on a side of the business not directly involved in the Ponzi scheme.

In February, Mark Madoff's wife petitioned a court to change her last name and the last names of their two children, saying her family had received threats and was humiliated by the scandal.

Just days ago, a court-appointed trustee filed a lawsuit seeking to recover any money from the scheme that had been paid to members of the Madoff family, including Mark Madoff's two children.

At least a half-dozen Madoff employees have also faced criminal charges.

A year ago, the trustee, Irving Picard, sued several relatives, including Peter, Mark, and Andrew Madoff, accusing them of failing to detect the fraud while living lavish lifestyles financed with the family's ill-gotten fortune.