Police without basic investigative skills such as the ability to lift fingerprints, and prosecutors who lack training to try terror cases, are some of the main reasons cited. Another daunting challenge: Judges and witnesses often are subject to intimidation that affects the ability to convict. The legal system's failure to attack terrorism is critical because it robs Pakistan of a chance to enforce a sense of law and order, which militants have set out to destroy.
It has "caused a sense of terror and insecurity amongst the members of society," said one of the country's top judges, Lahore High Court Chief Justice Khawaja Mohammad Sharif. The legal failures also call into question the government's ability to fight terrorism in any way except by using the army in military offensives or human rights groups alleged through targeted extra-judicial killings.
The United States has said repeatedly that its success in Afghanistan and throughout the troubled region depends on strong help from Pakistan against militants. Pakistani army offensives and US missile strikes have killed some suspected terrorist suspects in recent years in the rugged northwest near the Afghan border, where militant leaders and senior operatives are based. The head of the Pakistani Taliban, the group blamed for many of the 20 biggest attacks, was killed in a drone strike last August, for example.
Indeed, human rights groups have accused security forces of carrying out hundreds of assassinations of suspected extremists or sympathisers in the Swat Valley, which the army reclaimed from the Taliban last year, rather than even trying to prosecute suspects in court.
Authorities deny the allegations, saying they do try to use the legal courts. But their record is dismal. An Associated Press review found no convictions in the 20 largest and most high-profile terror attacks of the last three years. Many of the Pakistani court cases connected to those attacks which have killed nearly 1,100 people have dragged on for years, or have yet to make it even past the investigation stage and into the courts.
The handful of cases that have been decided have all resulted in acquittals though many of these defendants remain in custody while they are investigated in other cases, court officials said. By contrast, 89 per cent of terrorism cases in the United States have resulted in convictions since the attacks on Sept 11, 2001, according to a report this year by the Center on Law and Security at the New York University School of Law.
The recent acquittals of suspects in two of the most high-profile attacks -- the 2008 truck bombing outside the Marriott Hotel in Islamabad and last year's commando-style raid on a police academy in Lahore, have highlighted the problems plaguing the system. The verdict in the Lahore police academy attack seemed to defy explanation.
The only person captured during the eight-hour siege in March 2009 was caught on the academy grounds in possession of a hand grenade allegedly trying to blow up a helicopter. Other militants attacked the main building with automatic weapons and grenades, killing 12 people and wounding dozens.
But the man claimed he was an innocent garbage collector picking up trash, and was convicted in June only of weapons possession for carrying a hand grenade and sentenced to 10 years in prison. He was acquitted of involvement in the attack for lack of sufficient evidence.
Lack of evidence was also the reason given for the acquittal in May of four men on trial in connection with the suicide truck bombing that killed 54 people at the Marriott Hotel in September 2008.
Pakistani lawyers and law enforcement officials said weak investigations conducted by poorly trained and resourced police officers made it very difficult for prosecutors and judges to convict. "I think the man who really plays the most critical role is neither the judge nor the prosecutor, but it is the investigating officer who is in charge of the case who sits in the police station in a pretty shabby environment," said Ahmer Bilal Soofi, a Supreme Court lawyer and legal commentator.
"Everyone has ignored him consistently," Soofi said. The police also can by stymied by Pakistan's most powerful spy agency, Inter-Services Intelligence, which often detains suspects and conducts parallel investigations without notifying the police or presenting evidence at court. That was the case after the assassination of former Prime Minister Benazir Bhutto in December 2007, according to a UN report.
The lack of collected evidence forces prosecutors to rely heavily on witnesses, a problem in a country where there is no witness protection program. People who are asked to testify in terror trials are often threatened or killed by militants. "This system relies on witnesses, and in the incidents that take place there are no witnesses normally or they don't want to come forward," Akbar Nisar Khan, Former Police Chief of Mianwaliq said.
"If people are not confident that state institutions can protect them, then why should they come forward?" These threats often extend to others involved in terror cases, including policemen, prosecutors and judges, leaving them to decide whether to pursue convictions against suspected militants or protect themselves and their families.
In June, three men showed up at the house of anti-terror judge Asim Imam in the northwestern city of Peshawar and threatened him and his family if he didn't "behave" during the coming trial of Sufi Mohammed, a hard-line cleric with close ties to the Taliban, said the judge's father-in-law, Javed Nawaz Gandapur. That trial has been delayed.
