Photo/IllutrationJustice Minister Takashi Yamashita announces two hangings at a news conference on Dec. 27. (Jin Nishioka)

Two convicted murderers were executed in Osaka on Dec. 27, bringing the total number of hangings for the year to a record-tying 15.

The high number is due to the executions in July of 13 former high-ranking members of Aum Shinrikyo, the cult that carried out a deadly nerve gas attack on the Tokyo subway system in 1995, as well as other crimes. The cult members put to death included Aum's founder, Chizuo Matsumoto, who also went by the name of Shoko Asahara.

Justice Minister Takashi Yamashita, announcing the latest executions, said he signed the death warrants on Dec. 25.

Hanged at Osaka Detention House were Keizo Okamoto, 60, a former organized crime gang member, and Hiroya Suemori, 67, a former investment adviser. Okamoto once used the family name of Kawamura.

The two were found guilty of killing the president of an investment advisory firm and an employee in Osaka Prefecture in January 1988, stealing about 100 million yen ($906,000) and burying their victims after encasing the bodies in concrete. Their death sentences were finalized by the Supreme Court in September 2004, closing off all avenues of appeal.

However, a lawyer for Okamoto, noting that a request for a retrial had been submitted, was scathing that the hanging had been carried out before a decision was made by the court.

At the news conference announcing the hangings, Yamashita said the request for the retrial was not a factor in deciding to hold off on the execution.

"As a nation ruled by law, we must carry out judicial verdicts that have been finalized," Yamashita said. "The death penalty takes a person's life so I gave the order after a careful consideration of past records of the case and other factors."

The two hangings were the first signed by Yamashita since he became justice minister in October.

Since Prime Minister Shinzo Abe began his second stint as head of government in December 2012, his administration has carried out 36 executions.

Justice Ministry officials said there were now 109 death-row inmates whose sentences have been finalized.