The prosecution of alleged September 11 mastermind Khalid Sheikh Mohammed and four others restarts Tuesday, just days before the 20th anniversary of the attacks, stirring new hopes for justice and retribution.

Mohammed and his co-defendants, who have been locked up at the "War on Terror" prison at the US naval base in Guantanamo Bay, Cuba for nearly 15 years, will appear in the military tribunal here for the first time since early 2019.

But after a 17-month halt due to the coronavirus pandemic, the proceedings appear likely to continue where they left off, mired in the defense's efforts to disqualify most of the government's evidence as tainted by the torture the defendants underwent in CIA custody.

On Sunday, the new military judge, Air Force Colonel Matthew McCall -- the case's eighth -- signaled a slow start, deciding that an initial hearing focused on his own qualifications will take place on Tuesday. Lawyers for both sides are allowed in a war crimes tribunal to question a new judge for possible bias.

The rest of the week will mostly involve meetings with the military prosecutors and defense teams.

With scores of motions lined up to demand evidence that military prosecutors refuse to hand over, defense attorneys said the pretrial phase could easily last another year, placing far over the horizon any hope for a jury trial and verdict.

Asked if the case could ever reach that point, one defense attorney, James Connell, replied, "I don't know."

Lasting impact of torture

Attorneys say the five defendants -- Mohammed, Ammar al-Baluchi, Walid bin Attash, Ramzi bin al-Shibh and Mustafa al-Hawsawi -- are all weak and suffer the lasting effects of severe torture endured in secretive CIA "black" sites between 2002 and 2006.

Added to that, the attorneys say, is the cumulative impact of 15 years in harsh, isolated conditions since arriving.

They will appear in an ultra-secure military commissions courtroom surrounded by fences of razor wire, each with his own defense team.

In the audience will be family members of some of the 2,976 people they are accused of murdering two decades ago, as well as a large contingent of reporters to mark the confluence with the somber anniversary on Saturday.

The five face the death penalty on charges of murder and terrorism in the war crimes tribunal.

They are represented by attorneys assigned by the military, as well as pro-bono lawyers from the private sector and non-governmental organizations.

Open and shut?

Since the case started, prosecutors have regarded it as open-and-shut, even without the tainted information reaped from the brutal CIA interrogations.

Instead, prosecutors maintain that the defendants all provided solid evidence of conspiring in the 9/11 attacks during so-called "clean-team" interrogations conducted by the FBI in 2007, after the five arrived at Guantanamo.

But defense attorneys argue that the 2007 interrogations were hardly "clean" because the FBI also took part in the CIA's torture program, and their interrogations carried a similar menace.

The defendants, still feeling the impact of torture at that time, spoke to the FBI under the real fear that it would start again, the defense contends.

"Make no mistake, covering up torture is the reason that these men were brought to Guantanamo" instead of the US federal justice system, said Connell, who represents Baluchi.

"The cover-up of torture is also the reason that we are all gathered at Guantanamo for the 42nd hearing in the 9/11 military commission," he said.

Delays

To prove their case, the defense is demanding huge amounts of classified materials that the government is resisting turning over, on everything from the original torture program to conditions at Guantanamo to health assessments.

Defense lawyers also want to interview dozens more witnesses, after 12 already appeared before the court, including two men who oversaw the CIA program.

The demands have delayed the trial, but the defense blames the government for actively hiding materials relevant to the case.

Alka Pradhan, another defense attorney, noted that it took the government six years to admit that the FBI took part in the CIA's torture program.

"This case wears you down," she said.

"They are withholding things that are normal procedure in court."