Turkish intelligence agents are infiltrating mosques, monitoring underground Web sites and investigating Islamic front charities but are having little success penetrating Al Qaeda's (search) tight-knit cells, agents and anti-terror police say.
It is a common frustration around the world, with police in Italy, Britain and dozens of other countries finding it difficult to penetrate Al Qaeda, a loosely knit terrorist organization where family ties and close personal relationships are often key.
The Indonesian government's inability to prevent Saturday's suicide bombings on the island of Bali (search) — three years after a similar attack on the tourist haven and a month after the president strongly warned of the possibility of upcoming attacks — is the latest example of the elusiveness of Islamic terrorist groups and the need for better intelligence.
Turkey's recent arrest of Louia Sakka (search), a Syrian accused of planning to ram a boatload of explosives into a ship carrying Israeli tourists to southern Turkey, illustrates the challenges.
Sakka slipped into Turkey with a fake passport two years ago and was detained, but police said they did not realize he was an Al Qaeda operative and deported him to Syria.
He returned to Turkey and was caught in August only after an accidental explosion in the safe house he was using led neighbors to complain to police about a strange smell coming from the burning building. Police discovered more than 1,320 pounds of bomb ingredients in the house and later uncovered Sakka's alleged plot.
To gather information on Al Qaeda-linked groups, police here and in other countries have been trying to use Muslim informants to penetrate cells, but police are having trouble recruiting people who can infiltrate Al Qaeda, which has links often forged on battlefields in Chechnya (search), Bosnia (search) and Afghanistan (search) — and now Iraq (search).
"Al Qaeda is held together by bonds of friendship, kinship and discipleship," said Nick Pratt of the George C. Marshall European Center (search) for Security Studies based in Germany.
Paul Beaver, a British defense and security expert, said it took years for Britain to penetrate IRA cells, and infiltrating Al Qaeda is "a more demanding job. There has been some success, but not enough, as the July 7 attacks in London showed."
The London bombing on July 7, which left 52 dead from four suicide blasts on subways and a bus, was carried out by a homegrown Al Qaeda-inspired cell led by a Pakistani-born Briton.
In Bali, no one claimed responsibility for the suicide attacks that killed at least 22 people, but suspicion fell on the Al Qaeda-linked regional terror group Jemaah Islamiyah (search), which has also been blamed for the 2002 Bali bombings that killed 202 people, mostly foreign tourists.
Turkey has an advantage in investigating Islamic groups — with a 100 percent Muslim police force, as religious minorities are not accepted — but that has failed to translate into big gains.
One Turkish intelligence agent said it might be possible to infiltrate Al Qaeda sympathizers or supporters, but it's far more difficult to penetrate an operational cell discreetly planning and carrying out attacks, because the structure is built on a "lack of trust."
Cells operate independently and each cell leader knows only the person above him in the organization, said the intelligence agent, who spoke on condition of anonymity because of the secret nature of the subject.
Also, one cell leader may command several groups, the agent said. The leader will use one alias with one group and another with a different group, he said, so captured members of different cells give interrogators different names.
When Turkish police showed suspects pictures of Sakka, they identified him with different names, according to a police interrogation report obtained by The Associated Press.
Harun Ilhan, one of the key Al Qaeda suspects on trial for the Istanbul bombings in 2003, said they frequently changed code names.
Turkish authorities monitor more than 800 Turks who have fought in Afghanistan, Chechnya or Bosnia; they are also now monitoring people who have fought in Iraq, police say.
Turkish undercover police often join Friday prayers in certain mosques, trying to see who known suspects may be meeting and where they are going, said an anti-terror police officer, who spoke on condition of anonymity because he was not authorized to talk on the record.
Police also use cameras to monitor streets and airports in some major cities.
Sometimes the police make their presence obvious. During a recent Istanbul Islamic charity event to collect aid for Palestinians, some people seemed startled when a police radio began blaring under the jacket of a man attending the event. The man — clearly a plainclothes police officer — made no effort to turn off the radio, possibly to intimidate people.
Police and intelligence agents also tap telephones of suspected Islamic militants and try to intercept Internet messages, but security forces are also finding that task frustrating.
"Just as it was difficult to infiltrate Al Qaeda's inner circle in the real world, the chat rooms, Web sites, and computers of today's displaced network have become more challenging to observe," said Chip Ellis, coordinator of terrorism studies at the Memorial Institute (search) for the Prevention of Terrorism based in Oklahoma.
"Some of these have been around for years and have closed themselves to new members and encrypted their communications," he said. "Others are constantly relocating and resurfacing."
There are also legal barriers. Phone and Internet companies in the Netherlands, for example, have protested demands by the Dutch government that they store data such as Internet service provider addresses and phone calls for three years for police.
Authorities also are trying to convince militants to give up violence.
Following the 2003 truck bombings in Istanbul that killed 61, some Al Qaeda-linked suspects expressed regret for their role in the killings while under interrogation, but after they returned to their prison cells, "they were seen quickly returning to their militant views," said Emin Demirel, a Turkish terrorism expert and author of a new book titled "Al-Qaida Elements in Turkey."