LAS VEGAS (AP) — The former head of a Tokyo and Las Vegas investment firm was sentenced Thursday to 50 years in prison for bilking thousands of Japanese victims in what prosecutors called a $1.5 billion international Ponzi scheme that ranks among the largest-ever fraud cases in the U.S.

Defendant Edwin Fujinaga, 72, also was ordered to pay nearly $1.3 billion in restitution to victims, including many vulnerable retirees in Japan who were told they were safely investing in a medical collections business that could earn a 6% to 10% annual return.

Evidence at the trial showed that some lost their life savings while Fujinaga spent lavishly on himself, buying a Las Vegas golf course mansion, private jet, luxury cars and real estate in California wine country, Beverly Hills and Hawaii.

Chief U.S. District Judge Gloria Navarro called efforts by Fujinaga to apologize "offensive." She also ordered him to surrender $813 million in assets.

Fujinaga blamed changes in the dollar-to-yen exchange rate for problems while he headed MRI International Inc. for more than a decade. He said he was trying to clean up a corrupt medical accounts payable industry and is now so despondent that he has to take medication.

The judge rejected his explanation and acknowledged that the severity of his crimes approached those of convicted U.S. Ponzi schemers Bernard Madoff in New York, Allen Stanford in Houston and Scott Rothstein in Miami.

In court documents, prosecutors ranked Fujinaga several notches below Madoff, who was sentenced to 150 years in prison for bilking thousands of investors out of at least $20 billion, and Stanford, who is serving 110 years for a scheme involving more than $7 billion.

They put him on par with Rothstein, who is serving 50 years in a $1.2 billion case.

Navarro acknowledged the government could only document $813 million in cash investments in the case because MRI company books were incomplete before 2009.

But she agreed with prosecutor William Johnson, who said MRI had $1.56 billion in outstanding investments when the scheme collapsed in 2013. Johnson said it relied on "new investor money going out to old investors."

"Yes, I made mistakes. I tried to keep it going. I became reckless and people got hurt," Fujinaga said Thursday, standing slightly stooped in blue jail scrubs with thinning, graying hair. He kept his hands on the defense table.

"I humbly apologize to all the people of Japan for all the chaos I caused," he said. "I'm speechless that I can't fix it."

Navarro rejected a bid for leniency from Fujinaga's appointed defense attorneys, who disputed the amount and calculations of investor losses. They also pointed to Fujinaga's age and unspecified medical issues, saying he would have to live to 122 before he could be freed.

The judge reminded Fujinaga that she heard the evidence presented at trial that led jurors in November to find him guilty of 20 counts of mail fraud, wire fraud and money laundering.

"It's ridiculous for you to try to say it was all a mistake," Navarro said. "I find it pretty offensive, and I'm sure it's offensive to victims as well."

Two former MRI executives who worked with Fujinaga — Junzo Suzuki, 70, and his son, Paul Suzuki, 40 — were arrested in Japan following Fujinaga's trial and are being held in U.S. custody in Nevada.

They have pleaded not guilty in federal court to criminal fraud charges and face trial in October.

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