Yemen has deported four Cameroonian people who have been detained by the Political Security System since March 1995 without trial or convictions, HOOd said on Monday.

However, the body of the four's leader billionaire Donisan remains in Yemen after he died at the system in unclear circumstances six months after his arrest, it said, pointing out that no investigation into his death was opened.

A source at the organization confirmed the four including a lawyer were deported to their country last week and that they were accompanied by Red Cross officials. The billionaire died during treatment, the source said.

In 2005, the organization sent a letter to former Interior Minister Rashad Al-Alimi who said the foreigners had been arrested on sabotage charges. Al-Alimi, according to the organization, also said the four would face court, but that never happened.

HOOD knew about the case after the Cameroonians filed a secret complaint about their detention. Meanwhile, it urged Attorney General to investigate the Cameroonian's death and the arbitrary detention of the five.