Prime Minister Fumio Kishida said Wednesday he has read a letter from the family of a Sri Lankan woman who died in Japan in March while being detained for overstaying her student visa, and "firmly accepted their feelings."

In the letter, the family of Ratnayake Liyanage Wishma Sandamali, 33, sought to clarify what led to her death as they remain unconvinced by a probe conducted by Japan's immigration authorities that failed to determine why she died.

Two sisters of Ratnayake Liyanage Wishma Sandamali, a Sri Lankan woman who died in March 2021 following mistreatment at a Japanese immigration center, speak to reporters in Tokyo on Sept. 10, 2021. (Kyodo)

"I will urge the Justice Ministry to take necessary steps to ensure that an incident like this will never happen again," Kishida told a House of Representatives session as he offered his condolences.

He made the remarks in response to a question by Chinami Nishimura, a lawmaker from the main opposition Constitutional Democratic Party of Japan, who called for an investigation by a third party into the "outrageous" incident.

Wishma's death at the Nagoya Regional Immigration Services Bureau raised questions about whether the immigration authorities provided adequate care and attention.

Japanese Prime Minister Fumio Kishida (R) attends a House of Representatives plenary session in Tokyo on Dec. 8, 2021. (Kyodo) ==Kyodo

The Sri Lankan, who came to Japan in 2017 on a student visa, had been detained at the central Japan immigration facility since August last year. She died on March 6 after complaining of a stomachache and other symptoms from mid-January.

Wishma's family sent the letter addressed to Kishida in October, seeking a further probe to get to the truth and the release of materials such as video footage prior to her death, according to Nishimura, who called on the government to provide Wishma's autopsy results to her family.

Kishida said an investigation has already been carried out by the Justice Ministry based on objective materials and with opinions from third-party experts, adding that a portion of surveillance video footage showing Wishma before her death was disclosed to the family.

The investigation report released in August found that staff at the immigration facility lacked awareness of handling crises, and there were problems with the center's medical and information sharing system.

Wishma's family has filed a criminal complaint against senior officials of the Nagoya immigration facility, accusing them of failing to provide appropriate medical care and causing her death.

After hearing the parliamentary session, Wishma's sister Poornima, 27, who has been staying in Japan, told reporters that she was unconvinced by Kishida's remarks as the truth has yet to be clarified nine months after her sibling's death.

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