NEW YORK (AP) — The FBI agents who arrived at Bernard Madoff’s luxury penthouse apartment on the morning of December 11, 2008, found a broken man in a bathrobe who knew his time was up.

The one-time titan of finance confessed he had “paid investors with money that wasn’t there.” A year after Madoff’s scheme collapsed — with headlines of US$50 billion in losses — investigators and investors are still struggling to measure the full scope and impact of the largest securities fraud in history.

The scandal has already resulted in more aggressive enforcement and stiffer sentences for white-collar crime, and tougher regulations for the Securities and Exchange Commission.

Investigators are looking at other possible suspects — including Madoff’s closest family — in the massive fraud that sent the 71-year-old mastermind to prison for life, stripped his family of their earnings and wiped out the life savings of thousands of investors.

Losing everything in the Ponzi scheme is “not a nightmare I’m going to wake up from”, one investor, Sharon Lissauer, said in a recent interview.

“I wish I could wake up and turn the clocks back and have my money back,” the Manhattan model said. “It’s been a year but it seems like a lifetime.”

After an intense investigation, authorities still can’t account for all the money investors claim they lost, although some went to pay off other investors and to support his lavish lifestyle.

The epic swindle so far has resulted in a 150-year sentence for Madoff and the arrests of four underlings. A court order stripped Madoff’s wife, Ruth, of most of her wealth, forcing her to move out of the couple’s Manhattan penthouse. The family’s mansions, yachts and clothes have been auctioned off to repay investors.

There’s been enough material for a half dozen books to be published based on a now-familiar story: How Madoff rose to prominence in the 1980s as both a middleman between the buyers and sellers of stock and as an adviser to thousands of investors, many Jews like himself and Jewish charities; helped launch Nasdaq, the first electronic stock exchange; became so respected that he advised the SEC on the system; and lived a lavish lifestyle to rival some of his wealthy clients.

But behind the scenes at Bernard L Madoff Investment Securities, in a separate office kept under lock and key, Madoff was secretly using cash from new investors to pay returns to old ones.

Authorities say that over the years, an old IBM computer cranked out fictional monthly statements showing steady double-digit returns, even during market downturns. As of late 2008, the statements claimed investor accounts totalled US$65 billion, much of it phantom wealth because no securities were ever bought or sold.

Even after a year, authorities say the size of Madoff’s theft — and what investors can expect to get back — remains murky.

Attorney Stephen A Weiss, who together with a team of lawyers represents more than 100 Madoff investors, said he believes most will recover only a small portion of their losses.

“I believe it could be over 10 per cent,” he said. “I would find 25 per cent is probably an unrealistic goal.”

A court-appointed trustee is still trying to recover Madoff’s assets — sometimes by suing hedge funds and other large investors who came out ahead — and divvying up proceeds to victims.

A trustee, Irving Picard, said he had identified US$21.2 billion in real losses in about 2,300 customer accounts, but only located about US$1.5 billion in assets.

His multimillion-dollar homes in Florida, Manhattan and Long Island were put on the market and his belongings auctioned off, including boats, 17 Rolex watches — even Madoff’s Mets jacket.

Madoff pleaded in March to securities fraud and other charges, saying he was “deeply sorry and ashamed.” He was led off to jail in handcuffs to scattered courtroom applause from angry investors.

“To this day, he deeply regrets what he did,” Madoff’s attorney Ira Sorkin said yesterday. Sorkin made no excuses for his client, but said that Madoff isn’t evil.

“It’s something he got into that he couldn’t get out of,” Sorkin said.

Madoff’s sentencing in June ended his own legal saga. But authorities and experts say the fallout continues.

Federal prosecutors and the FBI, always sceptical of Madoff’s claim that he acted alone, have not ruled out charges against members of Madoff’s family and longtime associates.

“This case is not over,” said David Cardona, head of the New York FBI office’s criminal division. “The FBI continues to cover every lead.”

Still on the list of potential suspects is Madoff’s brother, Peter, an instrumental player in building Madoff’s investment firm, and sons Andrew and Mark, who worked for their father in a trading operation and turned him in. They have never spoken publicly about the case, but have denied wrongdoing through their lawyers.