Two former executives of a Japanese company that sells desalinated ocean water harvested from off the Kona Coast operated multiple schemes to steal millions of dollars from the company during and after their employment, according to a grand jury indictment unsealed this week in U.S. District Court.

Only one of the executives, Yasuhiro Hirayama, a former chief financial officer and board member of Koyo USA Corp., is charged with crimes in the December indictment.

The other, former marketing and communications manager Yutaka Ishiyama, is mentioned in the indictment only by the initials Y.I. According to other court documents, Ishiyama made admissions about the schemes to IRS investigators in August. He died in October.

A U.S. magistrate judge here granted the government’s request in October for a warrant to seize $811,547 that was in escrow from Ishiyama’s sale of his home in Washington state.

Koyo USA, a subsidiary of the Japanese company Koyo-Sha Co. Ltd., sells MaHaLo Hawaii Deep Sea bottled water in Japan and other parts of Asia.

According to the indictment and other court documents, Hirayama and Ishiyama persuaded their bosses to purchase bottle labels at a 110 percent markup from a California vendor without disclosing that they owned and controlled the vendor. They even created false documents to make it appear that the vendor produced the labels when in fact it purchased them from a true label manufacturer.

As part of the scheme, Melanie Edwards, another defendant charged in the indictment and the only employee of the California vendor, corresponded with Koyo from her home in Sherman Oaks, Calif., to keep up the ruse.

The vendor listed Edwards’ home as its office address and a rented post office box as its business address. The indictment says Hirayama, Ishiyama and Edwards defrauded Koyo out of more than $15 million in label purchases and commissions paid to Hirayama and Ishiyama from 2004 to 2014.

The indictment also says Hirayama and Ishiyama encouraged a Koyo employee to retain a Honolulu lawyer and threaten a sexual harassment lawsuit against the company. Hirayama and Ishiyama persuaded their bosses to let them handle the matter. They then created a phony law firm to negotiate a settlement with the employee.

Hirayama and Ishiyama reported to their bosses that the employee, a showroom manager, agreed to settle her sexual harassment, age and race discrimination claims against Koyo and the company’s chief operating officer for $2.46 million. The actual settlement amounts, which were paid to the employee’s lawyer, totaled $1.41 million. According to the indictment, Hirayama and Ishiyama pocketed the $1.05 million difference plus $364,510 that Koyo paid out for services the phony law firm never performed.

Another scheme detailed in the indictment involved the replacement of PVC pipes at Koyo’s processing plant at the Natural Energy Laboratory of Hawaii Authority’s technology park in North Kona. The indictment says the job cost $265,712 but that Hirayama’s accomplice, handyman Curtis Paza, billed the company $719,816. Paza, who is charged in the indictment, posed as the contractor while the work was actually performed by a licensed plumber.

Hirayama and Ishiyama are also accused of a fourth scheme, which involved presenting fake documents through a lawyer to demand severance payments from Koyo after they had stopped working for the company. The indictment says Hira- yama and Ishiyama claimed they were each due $800,000 plus five years of salary and health care benefits, and that Hirayama collected at least $2.8 million.

The indictment charges Hirayama, Edwards and Paza with multiple counts of wire fraud, money laundering and conspiring to launder money. The government has filed forfeiture claims against the defendants for more than $18 million in cash, five pieces of artwork valued at $91,466, and a 10-acre farm property in Kona that has a tax-assessed value of $2.5 million.