The Tokyo District Court on Thursday sentenced Isamu Kuroiwa, former chairman of the Tokyo-based investment firm World Ocean Farm, to 14 years in prison for defrauding investors in a scam involving a bogus shrimp farming business in the Philippines.

Six former executives of the World Ocean Farm, including Atsuhiro Kuroiwa, Kuroiwa's 29-year-old son who was in charge of its funding operations, were sentenced to two to three years in prison each for conspiring with Kuroiwa, 60, in the fraudulent scheme.

Presiding Judge Saburo Tokura determined Kuroiwa was "the main culprit who totally controlled the firm as an autocratic business owner" and said, "(He) inflicted irreparable financial damage on many people through a large-scale, slick organized fraud."

Kuroiwa was sentenced in May last year to three years in prison, suspended for five years, for fleeing overseas on a fake passport, but the suspension was nullified upon Thursday's sentencing.