TOKYO — Fake business cards, impostors at meetings and forged documents stamped with the company seal are behind what appears to be an elaborate scam that Lehman Brothers in Japan alleges bilked it of millions of dollars in investment money.

The alleged fraud is at the center of a $350 million lawsuit that Lehman Brothers Holdings Inc. filed last week in Tokyo and that has ensnared one of the biggest names in Japan's road to modernization and economic power — trading house Marubeni Corp.

Additional victims are popping up. And analysts say the unfolding scandal is a wake-up call about imperfect corporate governance and monitoring of rogue employees while this relatively insular nation is trying to attract foreign investment.

It is also a major embarrassment for Lehman, which is struggling to assuage investor worries that it doesn't have the same problems as Bear Stearns Co., which is being bought by JP Morgan Chase & Co.

On Tuesday, Lehman said it had raised $4 billion in new capital to shore up its liquidity position.

But if the tale of massive deceit — as pieced together from various parties — is true, Marubeni appears headed for an even bigger embarrassment that could raise serious questions about its credibility, internal controls and corporate governance.

According to a person familiar with the case, Lehman was approached in last August about investing in a healthcare business led by a man who was then the head of Asclepius Ltd., a Tokyo medical consulting company that has since gone bankrupt.

After Lehman invested some 35 billion yen ($350 million) in a hospital renovation project, it never got back more than a tiny part of the money it had been promised.

Lehman assumed the deal was backed by Marubeni because documents had the official company seal and meetings with Marubeni employees were at the company office, according to the source, who asked not to be identified because of the case's sensitivity.

A day after Lehman filed its suit, Medcajapan Co., a Japanese nursing care provider, said it lost 3.5 billion yen ($35 million) lent to a project related to Asclepius that Medcajapan believed was backed by Marubeni.

And FinTechGlobal Inc., a Japanese technology investor, says it may have been duped out of 2.2 billion yen ($22 million) in a similar scheme involving Asclepius and Marubeni.

Marubeni denies it's obligated to repay Lehman. It says two Marubeni employees, who have since been dismissed, were merely victims. At least one individual who claimed to be a Marubeni official appears to have been an impostor with a fake business card, the source said.

"Lehman Brothers has a legitimate claim against Marubeni, for allowing two 'rogue borrowers' within the firm to forge documents, forge seals and forge a deal — costing a not so shabby $352 million," Boston-based Aite Group senior analyst Phillip Silitschanu said in an e-mail.

"Once mighty firms such as Societe Generale and Lehman Brothers are now having to face that even they are not immune to the risks a nefarious employee can pose," he said, referring to the more than $7 billion rogue-trader scandal that surfaced earlier this year at the French bank.

Koetsu Aizawa, an economics professor at Saitama University, says the scandal underlines the zealousness at trading companies, which are struggling to regain their star role as brokers.

During the heyday 1960s and the subsequent decades of Japan Inc.'s growth, Marubeni and other traders — Mitsubishi Corp., Sumitomo Corp., Mitsui & Co. — engineered government projects and foreign aid programs, and acted as consultants.

In the 1970s, Marubeni was embroiled in the Lockheed scandal that involved alleged bribery to a prime minister. Another high-profile bribery scandal surfaced in 1992.

Marubeni also has a reputation for being a "silo" organization, in which sections are divided and know little about what other units are doing.

"Marubeni is inevitably going to be held responsible for oversight in managing its employees," Aizawa said.

"The case involves big names like Lehman and Marubeni," he said. "It's astonishing how no one saw through such a blatantly ludicrous scheme."