Refugee advocates who supported Mr Masri said the killing, outside a courthouse near the Khan Yunis refugee camp, might have been carried out by the Palestinian political party Fatah, which wrongly believed he was an Israeli collaborator. But sources in Gaza suggested the 31-year-old was killed to avenge his alleged involvement in the deaths of two members of a rival clan 18 months ago, part of a long feud.

A refugee advocate, Marilyn Shepherd, told the Herald last night she and Mr Masri's uncle, who lives in Adelaide, had submitted the application for a visitor's visa through the office of the Labor senator Linda Kirk in February, soon after the murder of Mr Masri's brother, "but the department put the red flag up on us". "He said all along that his life was in danger but they never believed him - when the Masri name came up, the shutters at the department went down. "He was gunned down in broad daylight in cold blood. His mother was killed before he claimed refugee status here, his brother was killed last year, and he was gunned down yesterday like a dog on the side of the road."

A spokesman for the Department of Immigration said last night the welfare of a person removed from Australia was the "responsibility of the country to which he has been removed. Anybody who has applied for protection from Australia is not removed if we believe that person will be persecuted." Mr Masri first arrived in Australia in 2001, suffering a bullet wound to the leg, but was detained at the Woomera detention centre after his asylum claim was rejected.

In 2002 Mr Masri, then 25, was twice released from detention by order of the Federal Court. The court ordered his second release from custody after the government detained him again near Port Augusta because he did not have a visa. The then immigration minister, Philip Ruddock, said that Mr Masri would be deported because he did not have a visa. Mr Ruddock could not be contacted for comment last night. As a result of the Masri case, which was taken to the High Court, six immigration detainees were released. The court found the Government had no power to detain them. The full bench of the Federal Court ruled that the immigration minister had no power to detain asylum seekers before they were deported.

A South Australian lawyer, Paul Boylan, said last night Mr Masri was a genuine refugee who should have been allowed to stay but was instead sent back and assassinated. "He told his story and notwithstanding he had already been shot once, he wasn't believed," Mr Boylan said. "We sent him back to a place where he was assassinated." The Jesuit priest Frank Brennan, a refugee advocate and author of a book on the immigration system, Tampering With Asylum, said it was clear that Mr Masri "like his brother, was a marked man".

Father Brennan, who knew Mr Masri well, described him as a young man who fled to a safe country in the hope that his family could follow. "He had a deep love of his wife and children, he wept for Palestine, and despite the dreadful adversity of Woomera, he always had a sense of humour." A spokesman for the Social Justice Network, Jamal Daoud, said the Howard government had blood on its hands. "The previous Australian government is responsible for another terrible crime by forcing refugees to be sent back to Gaza when they knew the situation there," he said. "This guy had problems with Israel and the Palestinian Authority. He claimed to have been tortured and the previous government knew all that and still forced him out. It is a tragedy because we have lost another young person who could have been a good Australian citizen."

with Penelope Debelle and AAP