Terrorist group Al Qaeda is believed to be behind the attacks that killed 2,977 people in the United States. While its leadership at the time is either eliminated or imprisoned, families of 9/11 victims still await justice as the five men in US government's custody for planning the attacks are yet to be convicted and sentenced.?

Their conviction and sentencing appears to be a distant hope as the trial is yet to start. After 22?years, the 9/11 case still remains in pre-trial stage. The next pre-trial hearing is later this month.?

Here we explain what happened on September 11, 2001, who carried out the attacks and who planned it, and why and how the trial is yet to start.

The 9/11 attacks explained

Nineteen terrorists of Al Qaeda hijacked four passenger planes on Sept. 11, 2001.?

One plane each was crashed into each of the World Trade Centre's towers in New York City, killing 2,750 people. A third plane was crashed into the Pentagon, the headquarters of the US Department of Defense, in Virginia, killing 180 people. The fourth plane was brought down in the fields of Pennsylvania when passengers and crew fought their hijackers to retake control of the plane. Forty people died in the Pennsylvania crash.

The destination of the fourth plane remains unknown but it's believed it could have been destined to US Capitol in Washington DC.

The pursuit of Al Qaeda leaders behind 9/11 attacks

The US government held the then-Al Qaeda chief Osama bin Laden and his fellow leaders of the terrorist group responsible for the 9/11 attacks. Khalid Sheikh Mohammed, often referred to as KSM, was the "principal architect" of attacks, according to the US 9/11 Commission.?

Following the attacks, the then-US President George W Bush launched the War on Terror in which much of the Western world joined the United States. A US-led international force invaded Afghanistan where 9/11 plotters were believed to have operated from. The US-led forces overthrew the Taliban regime in Afghanistan at the time that sheltered Al Qaeda. The?hunt continued for Bin Laden, who slipped away during the initial invasion.

Osama bin Laden was ultimately killed in a US special forces operation sanctioned by the then-US President Barack Obama in 2011. He was living with his family in a fortified compound in Pakistan. His deputy at the time of the attacks and successor Ayman al Zawahiri was killed in July 2022 in an air strike sanctioned by current US President Joe Biden.?

KSM, the principal architech of the 9/11 attacks, was captured in 2003 in Pakistan in a villa at a mere five-minutes drive from the Pakistan Army headquarters.?

The detention at Guantanamo Bay

Five persons are in US government's custody who are believed to be among the planners of 9/11 attackers. They are:

1. Khalid Sheikh Mohammad is accused to be the mastermind of 9/11 attacks. He was the number three of Al Qaeda after Bin Laden and Al Zawahiri.

2. Walid bin Attash is accused of training two of the hijackers how to fight to take control of the passenger planes.

3. Ramzi bin al-Shibh is accused of recruiting hijackers in Germany. He is also accused of being an intermediary between lead hijacker Mohammed Atta and Al Qaeda leadership.

4. Ammar al-Baluchi is accued of transferring money to hijackers.

5. Mustafa al-Hawsawi is also accused of transferring money to hijackers.

The five 9/11 attacks accused?are being detained in a facility in Guantanamo Bay, a US military base in Cuba. They are detained there to be prosecuted by a military commission.?

This medium of prosecution is controversial as they are not being prosecuted under the US federal laws but by a military commission. They are indefinitely detained at Guantanamo detention facility —often called Gitmo— and don't?have any protections otherwise offered by the US Constitution or federal laws.

The detention camp came up in 2002 to house terrorists accused of 9/11 and other acts of terror against the United States. It bypasses US laws and is often accused of?violating?Geneva Conventions and human rights.

"Since 2002, roughly 780 individuals suspected of terrorist involvement and belonging to some 50 different countries have passed through the military prison on foreign soil [Guantanamo detention facility], thus they are not subject to US?law and its Constitution. Hundreds have been released without charge, and some transferred to third countries," notes journalist Hollie?McKay.

Of the 780 people to have been processed through Gitmo, only two have been convicted so far. This is believed to be a grave failure of US counter-terrorism efforts, which have otherwise been hailed for its success to have prevented major jihadist attacks on US soil after 9/11 attacks and for also dismantling jihadist networks abroad to a great extent.

Why the 9/11 trial is yet to start?

The prosecution of the five 9/11 planners is still in the pre-trial stage. A key reason for this seemingly never-ending delay is the to and fro between the prosecution and defence over what evidence is admissible as lot of evidence and confessions have been obtained through "enhanced interrogation techniques" (EITs), which is often said to be a euphemism for torture.

"The torture allegations led to concerns that the U.S. might have ruined its chance to put Mohammed on trial in a civilian court," notes The Associated Press.

This is also a reason why the US government is reluctant to prosecute the accused on US soil under regular US laws as the accused would then have civil liberties and legal rights that might bring forth the alleged US abuses on them and others over the years.

Explaining the military commission under which the accused are being prosecuted, journalist Hollie McKay writes, "Per the updated Military Commissions Act of 2009 (conceived in 2006, reformed three years later and amended in 2011 and 2013 to give greater protections to defendants), a Convening Authority is appointed by the U.S. Secretary of Defense. The commissions amalgamate US federal criminal courts and the military court-martial system."

The pre-trial proceedings are also long because the US government wants to protect the classified intelligence and national security material that might become public, so there is lot of deliberation and to and fro between the prosecution and defence over "discovery of information".

"The defense lawyers want access to all information the government possesses about their clients’ abusive treatment by the CIA, including granular details about their torture. They insist it is necessary to provide effective legal counsel...The prosecution argues that documents containing the full details about the CIA’s now-defunct Rendition, Detention and Interrogation (RDI) program are too sensitive to share," writes Lisa Hajjar, Professor of Sociology at University of California Santa Barbara in an article for The Conversation.

Hajjar further notes that the US Central Intelligence Agency (CIA) argues that the case is about the actions of the accused leading to 9/11 attacks and not about what happened to them afterwards, with one prosecutor saying that "The CIA is not on trial".?

While this to and fro kept consuming time, the transfer of military judges also added to it. The proceedings were further stopped for 17 months because of Covid-19 pandemic. Despite the resumption of proceedings, hearings have been repeatedly cancelled over the past two years.

"The military commissions calendar shows that 9/11-related hearings were canceled in January, March, May, June, July, and September. There are pretrial hearings canceled in October and scheduled in November," reported Washington Examiner?last year.

The AP has reported that the accused and the US government have tried to negotiate?a plea deal where the accused could plead guilty but escape the death sentence. This is unacceptable to many, including the US Republicans.?

Last year, Republication Representative Mike Turner told Examiner:?"Khalid Sheikh Mohammed and his accomplices planned the Sept. 11 terrorist attacks [and are] responsible for the deaths of nearly 3,000 Americans. It is unconscionable that military prosecutors would even entertain the idea of a plea agreement that removed the possibility of the death penalty."

Rep. Michael McCaul, said: "If this case doesn't justify the death penalty, what does?"

Families of victims await justice amid all this. Gordon Haberman, whose 25-year-old daughter Andrea died in the 9/11 attacks, told The AP, "Now, I’m not sure what’s going to happen. It’s important to me that America finally gets to the truth about what happened, how it was done. I personally want to see this go to trial."

The next pre-trial hearing of the case is later this month, according to The New York Times.

Issues with protracted prosecution and possible way forward

David Kelley, a former US attorney who co-chaired the Justice Department’s nationwide investigation into the 9/11 attacks, called the delays and failure to prosecute "an awful tragedy for the families of the victims". He told?AP that putting KSM on trial before a military tribunal?rather than in the regular US court system is "a tremendous failure" that was "as offensive to our Constitution as to our rule of law".

Kelley further said that it becomes harder to prosecute KSM with the passage of time as "evidence goes stale, witness memories fail".

Hajjar suggested?two possible ways out of the problems.

"If the priority is to protect the CIA’s secrets, the death penalty should be taken off the table and plea bargain negotiations for life sentences should begin. If the death penalty remains a priority, the defense should be given access to all the information they seek, including, for example, the full Senate Select Committee on Intelligence’s report about the CIA’s rendition program," wrote?Hajjar in The Conversation.

The plea talks have already been tried, as confirmed by one of the accused's legal team to the AP.?

However, The New York Times last week reported that President Joe Biden has rejected conditions for the plea deals laid down by the accused.?

The case has further been complicated as one of the accused, Ramzi bin al-Shibh, has been excluded from the plea talks a military medical board last month ruled him incompetent to either face trial or offer a plea, reported NYT.