Jianwei Li and two other wealthy Chinese businessmen thought they had a sure thing when they wired $1 million each to a California firm that had promised to build a fine Chinese restaurant in the Bay Area city of San Bruno. The project had an alluring budget with multiple lucky 8s - $5,888,888 - and the three investors were assured it would create enough jobs to obtain the real prize: a U.S. green card. Months passed and nothing happened. When Li's friends cornered the project developer one evening at a karaoke bar, the man, identified in court papers as Sammy Lee, apparently devised a fantastic escape. "He went to the bathroom, fell to the ground and said he was having a heart attack," said Edward Lau, a San Francisco lawyer who won a default judgment this year against Lee and his associates. The ambulance came and took him to the hospital. But [the hospital] said he was never admitted. He kind of woke up and left the scene. Li and his co-investors had fallen victim to a fast-growing scam - fraud in the government program that gives wealthy people a pathway to U.S. citizenship as long as they are willing to pay. For a minimum $500,000 investment, a foreign investor can get a conditional green card. The card can become permanent if the project creates 10 jobs within two years. Little-known or used for many years, the number of these EB-5 visas, as they are known, has taken off recently, nearly doubling each year since 2009, in large part because of demand from wealthy Chinese. The program is likely to approach its annual cap of about 10,000 this year. Along with that rapid growth have come delays, weak oversight and increasing amounts of fraud that often have left millions of investors' dollars sitting in bank accounts as well as lives and businesses in limbo. The North American Securities Administrators Assn., an advocacy group, now ranks EB-5-related scams as one of the top new threats to investors. Overall, EB-5 visas are a small part of the 140,000 immigrant visas allotted annually on the basis of employment. But given the nation's budget crunch and continued high unemployment, lawmakers have called for expanding the EB-5 program. Other advanced countries aggressively use immigration policies to further their economic goals. Canada, Australia and Britain have investor-visa programs similar to the EB-5. Portugal and Ireland, hard hit by the Eurozone debt crisis, offer residency papers for big property purchases. And Spain, suffering from a glut of unsold homes, is considering giving visas for house purchases of as little as $210,000. "The underbelly is that once people started to see growth in this program, we started to see a lot more fraud," said Muzaffar Chishti, a director at the Migration Policy Institute, a nonpartisan think tank based in Washington. Chishti is wary about a ramp-up of EB-5 visas. "Any program that has a growth rate like that should be scrutinized ... especially when we have seen some pitfalls," he said. Behind the EB-5 boom is one huge source: China. For various reasons, such as better education for their children, 60% of the nation's millionaires are thought to be considering emigration, according to the Hurun Report, a Shanghai publication focused on Chinese wealth. About 80% of the 7,641 EB-5 visas issued in the last fiscal year went to Chinese investors and their immediate families, according to the U.S. Citizenship and Immigration Services agency, which oversees the program. Officials said China's soaring demand could soon trigger a quota for any one country. In the U.S., the EB-5 program has become a popular alternative to bank financing and bond sales by pooling investments from multiple individuals through so-called EB-5 regional centers. The EB-5 program has "tremendous potential" to create employment, said Patrick J. Leahy, (D-Vt.), the chairman of the Senate Judiciary Committee, which has oversight of immigration. In Southern California, EB-5 investors were behind the Marriott Hotel at L.A. Live and contributed $96 million toward projects in San Bernardino, creating about 4,000 jobs, city officials said. But there is little regulation of how promoters market visas to would-be immigrants. A number of projects have been shut down for failing to meet the government's standards for job creation. In many cases, developers have allegedly misrepresented their projects to investors or have misspent the funds collected.