The post-Sept. 11 war against terrorism is suffering as much in the courts as in the streets with several legal setbacks involving suspected members of Al Qaeda and other groups around the world.

The biggest reversal came in Germany when a court threw out the only conviction of a Sept. 11 suspect. But other cases have been hindered, too, including against a militant Indonesian cleric and Zacarias Moussaoui (search), the only alleged Sept. 11 conspirator charged in the United States.

The U.S. reluctance to let witnesses in custody testify and the sheer complexity of cross-border investigations are complicating factors for prosecutors.

And the Madrid bombings that killed 202 people last week showed that while investigators struggle to build judicial cases against suspects, terrorists are still successfully plotting and carrying out attacks.

Spanish authorities had one of the chief suspects in the Madrid bombings, Jamal Zougam (search), on their radar since at least 2001 as a possible Al Qaeda operative, even once searching his apartment, but were unable to build a case against him.

Zougam, arrested two days after the bombings, operated in at least two countries, Morocco and Spain.

The court decision in Germany to order a retrial for Mounir el Motassadeq (search) — charged with aiding the three Hamburg, Germany-based Sept. 11 hijackers — focused attention on the limits of international cooperation.

"The threat is a very broad global Islamic front where terrorist operatives of one nationality will go to a second country to plan a terror operation then move to a third country to carry out their attacks," said Richard Evans, editor at Jane's Terrorism and Insurgency Center (search) in London.

"Intelligence cooperation between countries like the United States and its allies has increased enormously, but there's still a long way to go," he told The Associated Press in a telephone interview.

In granting el Motassadeq a retrial last month, a German appeals court pointed to the lack of evidence from Ramzi Binalshibh (search), a Yemeni in secret U.S. custody who is believed to have been the key Al Qaeda contact for the Hamburg cell that included lead hijacker Mohamed Atta (search).

Judges ruled that the lower court, which found the Moroccan guilty in February 2003 of more than 3,000 counts of accessory to murder and belonging to a terrorist organization, failed to weigh how the United States' refusal to allow Binalshibh to testify influenced the case.

Fighting terrorism is no "wild, unregulated war," Presiding Judge Klaus Tolksdorf explained in the March 4 verdict, saying authorities' need for secrecy can't outweigh a defendant's right to a fair trial.

A German investigator in the case said the dilemma persists.

"Every country and every service has its own ideas and purposes and has to be careful with human sources and information or the politics of their country. So of course the flow of information is not one-to-one," said Manfred Murck, deputy head of the Hamburg state agency that tracks extremists. "Nobody gets the full information of the other services."

U.S. authorities provided German intelligence with interrogation transcripts from Binalshibh, who was captured in Pakistan on the anniversary of the Sept. 11, 2001, attacks in the United States. But they came with the proviso that the information not be used in court.

Even if they were allowed, Murck said the judges likely would have wanted the witness in person to evaluate the testimony.

The ban was also a key factor when the Hamburg state court found el Motassadeq's friend and fellow countryman Abdelghani Mzoudi (search) not guilty of the same charges last month.

In the United States, the federal conspiracy case against Moussaoui has stalled because the Justice Department refuses to let Binalshibh testify.

U.S. District Judge Leonie Brinkema in Virginia ruled that unless Binalshibh appears in court, she would ban any evidence connecting Moussaoui to the Sept. 11 attacks, and bar prosecutors from seeking the death penalty.

An appeals court is considering Moussaoui's right to question Binalshibh and two other Al Qaeda suspects.

While the United States never explained its stand in the Hamburg trials, government attorneys argued in the Moussaoui case that U.S. national security should override his right of access to the witness.

One reason behind the U.S. position may be that keeping operatives like Binalshibh incommunicado could keep prime suspects guessing, including Al Qaeda leader Usama bin Laden, who's still at large.

"If you're Usama bin Laden you have to be sitting around wondering if they're talking ... but if you produce one of them and he's not cooperating, that sends a clear signal he's not talking," said Walter Purdy, director of the Terrorism Research Center (search) outside Washington.

In Indonesia, a problem with witness access also emerged in the Jakarta trial of militant Muslim cleric Abu Bakar Bashir (search), suspected of Al Qaeda links and being a leader of the Jemaah Islamiyah extremist group.

Bashir has never been charged with terror activities blamed on Jemaah Islamiyah (search), such as the October 2002 Bali bombing that killed 202 people. But he was sentenced to four years in prison for treason, immigration and forgery.

At trial, three key suspects held in Malaysia and Singapore were only allowed to testify by video linkup. Defense attorneys argued they could have been under duress and the court discounted their statements.

The United States also refused to allow a witness in its custody to testify, providing investigators' notes in which the man implicated Bashir. Attorneys argued the evidence was inadmissible, and the judges ignored it.

Bashir's sentence was reduced on appeal to three years after a court annulled the treason conviction. Last Tuesday, the Indonesian Supreme Court halved that sentence as too harsh for the remaining charges and Bashir is now scheduled to be released next month.

The question now is whether Washington will give Indonesian authorities access to another key witness it is holding, suspected Jemaah Islamiyah operations chief Hambali (search), who is believed to be able to link Bashir to terror attacks, said Sidney Jones, who has followed the case for the Brussels-based International Crisis Group (search).

"They can't just work with interrogation reports," she said in a telephone interview from Jakarta.