Quotes of the Day

If the old police adage that most murders are solved in the first 24 hours is true, the investigation into the suicide bombings that killed 23 in Bali on October 1 could be in very deep trouble. Three weeks after the attacks, police and security officials working on the case say that they are at a standstill, no closer to identifying the three men who carried out the attacks and still clueless even about what kind of explosives were used. Five arrests have been made but all those detained have now been cleared and released. The brick wall the investigators face is a stark contrast to the first Bali bombing: three weeks after the October 12, 2002 attacks that killed 202, police had already made several key arrests, the first detentions in a sweep that eventually netted all but a few of the plotters.

Why the big difference? For one thing, vehicles were involved in both the original Bali attacks and subsequent bombings of the JW Marriott Hotel and Australian Embassy in Jakarta by Islamic radicals linked to the regional militant network Jemaah Islaimyah (JI). Their metal frames absorbed some of the blast—and also retained telltale traces of the explosives used. The most recent bombings, in contrast, were carried out by individuals on foot, carrying backpacks filled with explosives that they detonated once they reached their targets. (Though there is doubt about that, too. Police say the men could have been "involuntary suicides," whose bombs were set off by others with so-called "chicken switches," remote control triggers—usually mobile phones—commonly used in case of a last-minute failure of nerve). With no vehicles to absorb the explosions, the blasts were widely dispersed, leaving only exasperatingly tiny traces of explosive residue for police to work with, a security official familiar with the investigation says.

Compounding the problem is contamination of the blast sites, according to the security official. In the case of the two bombers who killed a dozen diners on Jimbaran beach, controlled explosions by police to detonate suspicious packages in the area following the attacks added separate traces of explosive residue to the mix. "It will be at least a couple of weeks before we have any idea what the explosives used were," the official says. The difficulties in identifying the bombs have also led police to conclude that they were much more sophisticated than previous devices, most of which involved large amounts of the fertilizer ammonium nitrate. The men who made the latest bombs were "experts," Bali police chief I Made Mangku Pastika told reporters on Oct. 21 when asked about the stalled investigation.

The other main line of inquiry, attempting to identify the bombers using photographs of their mangled but still-recognizable heads, has also drawn a blank despite the distribution of thousands of photographs on Indonesia's main island of Java, where police suspect the bombers were recruited. According to Sidney Jones, an expert on JI and head of the Southeast Asia office of the International Crisis Group, an independent think tank, there are several possible reasons why no one has come forward to identify the men. "It could be that the places that produced these men are closing ranks," she says, perhaps frightened of what might happen to their villages or families if they come forward. She also notes that the bombers are likely from a new generation of recruits who have no criminal records ("cleanskins" in security jargon). That means that the scores of terror suspects currently detained in Indonesia have been in jail long enough to be unfamiliar with new recruits and unable to provide any information on them.

Whatever the reasons, the stalled investigation is alarming some Indonesian security officials, who say they are concerned that the three men were unlikely to have trained for their gruesome mission alone. And if there are other suicide bombers out there primed to sacrifice their lives, new attacks might be imminent. "Suicide bombers have a sell-by date,"Jones says, noting that the motivation and sense of mission instilled by their controllers wanes within weeks and makes it likely that the bombers will lose faith in their tasks if not deployed rapidly.

• Simon Elegant
• Three weeks after suicide bombings killed 23 people, Indonesian investigators are no closer to finding those responsible