Two death row inmates who killed a company president and an employee at the firm were hanged Thursday morning in Osaka, the Justice Ministry said, bringing the number of executions in the country this year to 15.

The executions were the first carried out since 13 former members of the Aum Shinrikyo cult were hanged in July and the first ordered by Justice Minister Takashi Yamashita.

The two convicts were 60-year-old Keizo Okamoto, an ex-yakuza, and Hiroya Suemori, 67, a former investment adviser. They were hanged at the Osaka Detention Center.

They were both sentenced to death in September 2004 for fraud, kidnapping and murdering a president and worker of an investment company, as well as orchestrating another scam targeting a brokerage firm.

The two were convicted of kidnapping and strangling 43-year-old Kazuo Kengaku, the president of investment firm Cosmo Research Corp., in an apartment building in Osaka on Jan. 29, 1988, after robbing him of some ¥100 million in cash.

On the same day, they murdered Hiroyuki Watanabe, a 23-year-old employee of the investment firm. Watanabe had earlier been tricked into giving the two killers information about Kengaku’s whereabouts. To conceal the heinous crime, Okamoto and Suemori buried the two bodies in concrete and dumped them in a mountainous area of Kyoto Prefecture.

Okamoto and Suemori also took stocks worth ¥140 million from a brokerage firm and both were found to be illegally in possession of guns.

During a hastily arranged news conference Thursday morning, Yamashita called the crimes “extremely atrocious,” and said it was clear the two convicts had committed murders solely for selfish purposes.

“These crimes were ultimately vexing not only for the victims but also the surviving families,” Yamashita said. “They were extremely heinous and shook the nation.”

He explained the two inmates were guilty of robbery, murder, fraud, dumping the murdered bodies and violating the firearm and explosives control laws.

Yamashita, who signed the execution orders on Tuesday, said the hangings were carried out after “careful examinations” that determined there was no valid reason to conduct retrials.

2018 has now tied 2008 for the most executions in a single year since 1993, when Japan resumed use of the death penalty. Thursday’s hangings brought the number of executions under the current administration of Prime Minister Shinzo Abe, who retook office in 2012, to 36.

As of Thursday, 110 inmates are on death row. Of that number, 86 are seeking retrials, he said.

Yamashita acknowledged the severity of such punishment, but also said that abolishing the death penalty “would not be appropriate,” when asked about international calls to put an end to capital punishment in addition to criticism that labels Japan’s system as cruel and secretive.

“In the case of crimes conducted against a large number of people, or crimes that are extremely cruel or atrocious, the death penalty is absolutely necessary,” Yamashita said.

The Japan Federation of Bar Associations has called for capital punishment to be abolished by 2020 and replaced with lifetime imprisonment instead.

Human rights advocacy group Amnesty International Japan strongly criticized the government’s decision to execute the two inmates.

Amnesty’s Executive Director Hideaki Nakagawa told The Japan Times that the decision was “very disappointing,” given that the hangings were carried out just five months after the executions of the 13 Aum cultists.

He also said that the hanging of Okamoto was problematic given that he had requested a retrial and was waiting for a decision.

“Now as the world is trying to abolish the practice, Japan’s stance looks like the nation is going against such efforts,” Nakagawa said, noting that earlier this month, a total of 121 countries signed a moratorium on the death penalty and have declared they are seeking its worldwide abolition.

Earlier this month, a group of Japanese lawmakers was established to discuss the future of the system. More than 50 lawmakers from ruling and opposition parties are taking part in the discussion.

Information from Kyodo added