Image source, Getty ImagesImage caption, Poornima Sandamali holds a press conference in August holding a portrait of her late sister Wishma, who died in Japanese custody in March.

The family of a dead Sri Lankan woman have filed a criminal complaint against Japan immigration authorities, accusing them of failing to provide her with adequate medical care, say reports.

Wishma Sandamali, 33, died in March after being detained since August last year for overstaying her visa.

The move is believed to be aimed at pushing prosecutors to look further into the circumstances of her death.

The case has sparked scrutiny over Japan's treatment of detainees.

The complaint was filed against several senior executives, including the head of the detention facility where she was held, along with officers who were in charge on the day she died.

The bureau has declined comment, stating it was "not in a position to do so."

Local media reports say her family submitted a complaint to the Nagoya District Public Prosecutor's Office on Tuesday evening.

The family's lawyer Chie Komai had earlier confirmed to the BBC that a submission would be made.

  • The 'forgotten' Afghan refugees taking their own lives
  • What happens to migrants who reach the UK?

Sandamali, who came to Japan in 2017 on a student visa, had reportedly first sought help for domestic violence from Japanese authorities in August 2020.

She was instead placed in detention at Nagoya Regional Immigration Bureau for overstaying her visa.

According to activists who visited her, her health continued to deteriorate from extreme stress until she died in March, reportedly from emaciation.

Asylum bill pulled as pressure builds

Her death sparked outrage in Japan, causing some people to protest on the streets, demanding more information on how she died.

Repeated demonstrations also broke out in Nagoya, Tokyo and Osaka. A petition circulated by students and foreigner support groups calling for the release of all security camera footage of her garnered more than 93,000 signatures.

The outcry gained more momentum when partial cell footage released to the family and their lawyers by immigration authorities showed them failing to call an ambulance despite her appearing to be increasingly weak and unresponsive in the days leading up to her death.

Sandamali's family said the conduct by the immigration bureau amounted to wilful negligence.

A government agency's report into her death released in August also found immigration officials had failed to share details about her illness and that staff showed a lack of awareness of human rights.

While Sandamali was not an asylum seeker, her case has cast a spotlight on Japan's overall treatment of detainees trapped in the country's immigration system.

The public outrage over her case forced Japan to scrap a controversial bill that would have made it easier to deport failed asylum seekers.

Under the proposed bill, asylum seekers would have been granted a maximum of two applications before being deported. Previously, there was no limit as to how many times an application could be renewed.

Japan's strict asylum regulations result in fewer than 1% of applicants being accepted each year. This is significantly less than other developed nations like the US or European countries where acceptance rates are between 30% to 40% or higher.

Reporting by the BBC's Zubaidah Abdul Jalil

This video can not be played

To play this video you need to enable JavaScript in your browser.Media caption, Seeking asylum in Japan 'like being in prison'