A Chinese man on death row for the 2003 slaying of a family of four was executed in Fukuoka on Thursday, marking the first inmate put to death since Justice Minister Masako Mori took office Oct. 31.

Wei Wei, who had studied in Japan, was sentenced to death for the murder-robbery of a family in Fukuoka Prefecture. The victims included an 11-year-old boy and an 8-year-old girl.

“For a self-serving purpose, the convict killed all the family members. … This is an extremely ruthless crime,” Mori said during a news conference.

“We regarded very seriously the killing of four innocent people.”

Wei, 40, conspired with two other Chinese men and killed Shinjiro Matsumoto, 41, a clothing dealer, his wife, Chika, 40, their son, Kai, 11, and daughter, Hina, 8, on June 20, 2003, and stole about ¥37,000 in cash. Their bodies were found the same day in Hakata Bay, handcuffed and weighted down with dumbbells.

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The two accomplices fled to China where they were arrested. One of them was executed there in 2005 and the other was given a life sentence.

Wei’s death sentence was finalized in 2011. Prior to the murder, the three had been involved in various robberies.

In a statement released on the same day, international human rights group Amnesty International’s Japanese arm lambasted the execution of Wei, noting that it went ahead while he was seeking a retrial.

“Appealing for a retrial is part of the processes stipulated in the criminal procedure law,” the group said.

“They should have begun a process for suspending the execution while he was demanding a retrial. Failing to do so runs counter to the international human rights law.”

The statement also said Japan is turning its back on the global trend to abolish capital punishment, with more than 70 percent of the countries in the world having done away with the system legally or effectively.

In 2018, the group logged at least 690 executions — the lowest number in 10 years — in 20 countries including Japan, compared with at least 993 executions in 23 countries a year earlier, according to its report released in April.

In an interview with reporters shortly after assuming her ministerial post, Mori defended the nation’s capital punishment system.

“In cases of extremely brutal and heinous crimes, such a form of punishment is unavoidable,” she said.

She added, however, that imposing the death penalty requires thorough consideration from various angles and due process.

The last time the death sentence was carried out was Aug. 2.

The latest execution has brought the total number of hangings since the start of Prime Minister Shinzo Abe’s current tenure in 2012 to 39.

There are currently 111 prisoners on death row, the ministry said.