Japanese authorities bowed and offered flowers at the grave of a businessman to apologise for wrongfully charging him with exporting potentially sensitive industrial machines.

Shizuo Aishima and three other executives were arrested for illegal exports in March 2020. He died of stomach cancer in February 2021, five months before the indictments were dropped.

His family was at his grave in Yokohama on Monday to accept the apology. However, his wife said she could not forgive those who were behind the charge.

Aishima’s company sued for damages before a Tokyo court in September 2021, which ruled that the indictments were illegal and ordered compensation of 166 million yen ($1.12m; £835,000).

The charges stemmed from Ohkawara Kakohki’s export of spray dryers, a machine that can turn liquids into powder, and which can be used in the military.

The company said their business was not covered by export restrictions. Prosecutors withdrew the indictments in July 2021 citing “doubts” on the guilt of the accused.

“We sincerely apologise for the serious human rights violation caused by illegally requesting his detention and filing a prosecution, and for depriving Aishima of opportunities for medical treatment by inappropriately rejecting his bail request,” said prosecutor Hiroshi Ichikawa.

Aishima filed eight bail requests, all of which were denied.

The Tokyo Metropolitan Police Department and the Tokyo District Public Prosecutors Office did not appeal court ruling that ordered them to pay compensation. The ruling became final last 11 June.

They also investigated the cause of the wrong indictment. However, the families of the wrongfully accused said it failed to determine the real cause of the error and that the recommended punishments were too light.