The cause of death for Mark Madoff was released Sunday by the city's medical examiner's office.
The body of Mark Madoff was found Saturday morning hanging in his loft apartment while his 2-year-old son slept nearby. It was the second anniversary of the day his father was arrested in the worst investment fraud in American history.
Mark Madoff had been targeted by authorities as someone who failed to blow the whistle on his father's fraud, but he had maintained that he alerted authorities when his father confessed.
Bernie Madoff is serving a 150-year prison sentence after pleading guilty to fraud charges.
Mark Madoff had reportedly learned in the last week that he faced possible criminal charges in both London and New York.
Madoff left behind several emails, including one to his wife, Stephanie, telling her that he loved her, but no explanation of why he chose to take his life.
He also sent one to his wife and to his father-in-law asking that someone come to get the couple's two-year-old child.
Upon receiving the emails, which were written in the early morning hours after 4 a.m., Stephanie, who was in Florida with at least one of the couple's other children, contacted her father. He came to the apartment and found his son-in-law hanged in the living room around 7:30 a.m. Saturday, police said. The two-year-old was sleeping peacefully in a bedroom nearby, police sources said.
Madoff had used a black dog leash to hang himself, police said. His labradoodle, Grouper, was found nearby.
According to sources close to the family no one could have seen the suicide coming, although Madoff, 46, had been distraught, felt unemployable, and was sure that he would never be able to extricate himself from the thickets of notoriety.
"If he asked the question, 'Would my wife and children be better off without me?' the answer would probably be yes,' '' said one person familiar with his circumstances told ABC News.
In a statement, Mark Madoff's attorney, Martin Flumenbaum, said, "This is a terrible and unnecessary tragedy. Mark was an innocent victim of his father's monstrous crime who succumbed to two years of unrelenting pressure from false accusations and innuendo. We are all deeply saddened by this shocking turn of events."
Mark Madoff and his brother, Andrew, were under investigation but hadn't faced any criminal charges in the massive Ponzi scheme that led to their father's jailing.
Bernard Madoff swindled a long list of investors out of billions of dollars and is serving a 150-year prison term in North Carolina. He was arrested on Dec. 11, 2008, after confessing his crimes to his family.
Madoff's sons, according to the family's attorneys, were the ones who turned him in.
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 both worked on a trading desk at the firm, on a side of the business that wasn't directly involved in the Ponzi scheme.
A year ago, the court-appointed trustee trying to unravel Madoff's financial affairs sued several relatives, including Peter, Mark and Andrew, accusing them of failing to detect the fraud while living lavish lifestyles financed with the family's ill-gotten fortune.
The lawsuit accused Mark Madoff of using $66 million he received improperly to buy luxury homes in New York City, Nantucket and Connecticut.
In February, Mark Madoff's wife petitioned a court to change her last name and the last names of her children, saying her family had gotten threats and was humiliated by the scandal.
Calls to the FBI and U.S. Attorney's office were also not immediately returned. Previously, spokespeople for the brothers had repeatedly denied that they had any knowledge of their father's crimes.
Police investigators were at Madoff's apartment Saturday morning, along with officials from the medical examiner's office, which will determine the cause of death.
Timeline: Events leading up to Mark Madoff's death
Dec. 11, 2008: Bernard Madoff is arrested after telling senior employes that his investment company was "basically, a giant Ponzi scheme," and he had "absolutely nothing." Media reports later identified the employees as his sons, Mark and Andrew.
Dec. 12, 2008: Losses from Madoff's scheme are estimated to top $50 billion by his own account. Authorities would later put the loss at $20 billion, making it the biggest investment fraud in U.S. history.
Dec. 23, 2008: French investor Rene-Thierry Magon de la Villehuchet is found dead after committing suicide after he discovered that he had lost his entire savings, and his clients' money, to Madoff's Ponzi scheme.
March 12, 2009: Bernard Madoff pleads guilty to 11 charges, including fraud, perjury and money laundering. He gets a prison sentence of 150 years. The judge jails him immediately after the plea.
March 17, 2009: Federal prosecutors tell a judge they want to seize jewelry, business interests and more than $30 million from Madoff's relatives, including loans Madoff made to his sons, Mark and Andrew.
June 29, 2009: Bernard Madoff's wife, Ruth Madoff, breaks her silence and publicly says she was among the victims of her husband's deceit. She said he "stunned us all with his confession and is responsible for this terrible situation in which so many now find themselves."
July 2, 2009: Federal marshals force Ruth Madoff out of the $7 million Manhattan penthouse where she and Bernard Madoff lived.
July 14, 2009: Bernard Madoff arrives at prison in North Carolina to serve his 150-year sentence.
Aug. 3, 2009: Ruth Madoff is ordered to report expenses above $100 to a trustee appointed to locate and liquidate Madoff's assets to pay back thousands of burned customers.
Oct. 2, 2009: Court-appointed trustee Irving Picard sues Bernard Madoff's family members in U.S. Bankruptcy Court in Manhattan, claiming they used the family business as a "piggy bank." Mark Madoff is accused as improperly using $66 million from the business to buy luxury homes in New York City, Nantucket and Connecticut.
Feb. 24, 2010: Mark Madoff's wife Stephanie files court papers asking change her last name to Morgan from Madoff. She said the change would help her avoid "additional humiliation" and harassment that included threats. Mark filed papers saying he did not object to the move.
Dec. 8, 2010: Court trustee Picard files a lawsuit in London seeking to recover at least $80 million from the international arm of Madoff's business. Defendants include Mark and Andrew Madoff.
Dec. 10, 2010: Picard files civil racketeering charges against Austrian banker Sonja Kohn and 55 other defendants demanding that they give up nearly $20 billion, and accusing Kohn of accepting at least $62 million in secret kickbacks from Madoff for soliciting investors for the fraud.
Dec. 11, 2010: Mark Madoff is found dead in his New York apartment after apparently hanging himself while his 2-year-old son was sleeping in a nearby room.
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