He also said Bel Bacha, an Algerian army veteran, feared he would be hunted by al-Qaeda's North African affiliate because he worked for a government-owned oil company and had been called for another term of military service.
Katznelson said his client would rather stay in Guantanamo than return to Algeria.
Navy Commander Jeffrey Gordon, a Pentagon spokesman, said: "Detainees are not repatriated to countries where credible assurances of humane treatment cannot be guaranteed."
He declined to comment specifically on Bel Bacha's case.
But the US state department has noted, in a 2006 report that cites international and local rights groups, that Algeria's security forces have been accused of torturing suspects.
Stuffing a rag into a suspect's mouth while forcing contaminated liquids into the stomach until the person vomited was the preferred method because it left no traces of assault, the report said.
A US military spokesman said the US requires pledges that countries receiving detainees from Guantanamo will treat them humanely.
Human rights groups have dismissed such assurances as worthless.
The Pentagon alleges Bel Bacha had weapons training in Afghanistan and twice met Osama bin Laden, the al-Qaeda leader.
|More than 300 people remain incarcerated |
at the US's Guantanamo Bay prison [AP]
A recent military review process, though, determined Bel Bacha did not pose a threat and found him eligible for transfer.
Bel Bacha had lived briefly in the UK, where he worked as a waiter before his capture in Pakistan.
Lawyers have lobbied the British government to accept him, along with other British residents held at Guantanamo, but the UK has refused because the detainees do not have British citizenship.
Bel Bacha was taken to Guantanamo more than five years ago and is held in a solid-wall cell by himself for up to 22-hours a day.
About 80 detainees at Guantanamo are currently awaiting transfer, but another 360 remain incarcerated at Guantanamo, where most are in their sixth year of detention without charges.
A US military study that says the majority of Guantanamo detainees are a "demonstrated threat" was criticised on Thursday.
"What they've done is attempt to create a new category called 'dangerous people.' And they have a hierarchy - tier one, tier two, tier three dangerousness"
The study, commissioned by the Pentagon, reviewed unclassified summaries of evidence against 516 detainees who were processed by tribunals at Guantanamo Bay in 2004 and 2005.
Based on this evidence, the study found that 73 per cent of the detainees were a "demonstrated threat", but six posed no threat and the others were either "potential threats" or "associated threats".
But Mark Denbeaux, a professor at Seton Hall University Law School in New Jersey and the leader of another report on Guantanamo detainees, called the assessment "reverse engineering".
"What they've done is attempt to create a new category called 'dangerous people'. And they have a hierarchy - tier one, tier two, tier three dangerousness," he said.
"It's really reverse engineering. They looked at the data, tried to find facts and created categories."
Denbeaux's report found that only eight per cent of detainees had been described by the US military as al-Qaeda fighters and that 55 per cent had not committed any hostile acts against the US.
Denbeaux said: "They want to shift the debate from whether they are enemy combatants - and the fact that they are not enemy combatants by a definition everybody accepts - to a new category ... which is that they are dangerous."
But the military report said Denbeaux's team had used too narrow a set of criteria in evaluating the evidence against the detainees.
Bryan Whitman, a Pentagon spokesman, defended its report: "The department is confident that the CSRT (Combatant Status Review Tribunal) process as it is designed to determine enemy combatant status is sound and working effectively."
He said that the military has declared detainees "no longer enemy combatants" after annual reviews and transferred them to their home countries.
The variables used in the Pentagon's study to classify a detainee as a "demonstrated threat" included whether he had been identified as a fighter, had trained at an al-Qaeda or Taliban camp or had received weapons training beyond small arms.
At the other end of the scale, those deemed an "associated threat" had a "connection" to a member of al-Qaeda or other group, had stayed at a "suspect" guest house, had travelled to three or more countries, or were carrying large amounts of foreign currency.