The parents of an Iranian who died at a Tokyo Regional Immigration Bureau detention center in August 1997 filed a 93 million yen lawsuit Friday against the Japanese government.According to the suit, the man, Mousavi Abarbekouh Mir Hossein, 28, died on Sept. 9 last year in an assault by security officers at the facility in Tokyo's Kita Ward after being taken to a hospital unconscious and with injuries.He was imprisoned in the facility after receiving a suspended sentence from the Tokyo District Court in July for theft as well as for immigration and refugee law violations.His parents alleged in Friday's suit that their son died from repeated blows from a number of bureau employees, which resulted in numerous cuts to the face, hands and legs and internal bleeding. The immigration bureau has said that several employees took hold of Hossein but denied they assaulted him.In February police referred eight security officers to the Tokyo District Public Prosecutors Office for causing bodily injuries that caused Hossein's death. However, prosecutors decided a month later not to pursue the case.