The operators of the warung food stalls in the train station in the affluent Jakarta neighbourhood of Menteng were clustered around television sets late last Thursday.

It was not the usual diet of hyperbolic Indonesian soap operas or martial arts action flicks that had captured their fancy, but a news report of the latest terror arrests: 19 people were in custody over a series of book bombs sent to prominent Jakarta figures last month, their arrest uncovering a plot to attach bombs to a gas pipeline near a West Jakarta church to unleash carnage on Good Friday.

Most of those arrested were university graduates and had no clear links with major terrorist or extremist networks. A 20th, arrested later, was a television cameraman recruited by the group to film the attack.

The latest arrests come just a week after a bombing at a mosque in the West Java city of Cirebon and a few months after violence against the Ahmadiyah minority left three dead.

The cumulative effect is a country on edge, fearful of slipping back to the dark days of the first half of the 2000s, where terror tore at the heart of this emerging democracy and economy. But where the perpetrators of those attacks were generally known, the latest events appear to be localised and lacking a central organising force.

Which, in a way, makes them even more worrying — a thousand clusters of discontent is much harder to monitor than a centrally controlled organisation.

The details of the thwarted Good Friday bombing plot are gruesome. The plotters had attached several kilograms of explosives to a gas pipe at a Catholic church in Serpong, Tangerang, setting them to go off during the morning service.

The plot was uncovered by largely by accident. The 19 were arrested over the book bombs and it was only then that the church plot was uncovered.

The Cirebon bombing was a curious one. The perpetrator has so far been dismissed as a troubled individual already wanted over the murder of an army officer, his links to any groups unclear. His choice of target — a mosque inside a police complex — and the fact that his was the only fatality in the attack, suggest it was not the brightest mind at work.

While that attack could be explained as the product of a disordered mind, the mob violence directed at the Ahmadiyah community does point to deeper tensions. The February 6 attack, in which a mob of hundreds attacked a group of 25 in the West Java village of Cikeusik while police officers watched on, amounted to a racially motivated pogrom on the Ahmadiyah, which its attackers believe is an illegitimate strand of Islam.

The brutality of the attacks and the selection of the target have prompted some Pastor Niemöller-type thinking (“First they came …”). Perhaps mindful of the plight of the Ahmadiyah, a separate Islamic splinter group, the Millata Abraham Muslim sect, last week underwent a mass conversion to the faith’s mainstream.

It is not just the Indonesians who see worrying signs in the latest developments. Following the bomb plot arrests, Australia made mention of the fact in its travel advice for the archipelago that the Indonesian Government had moved onto the highest level of national vigilance in the wake of the arrests.

And the International Crisis Group has bought in to the issue, arguing the shift towards smaller groups and independent operators is a product of effective law enforcement thwarting larger organisations and an ideological shift towards more “individual” jihad.

Religiously motivated violence enjoys almost no support among the mainstream political class. It also has very little among ordinary Indonesians, who see it as a force that might not only undermine its physical security, but also put at risk its economic growth, which this week was found to have grown north of 6% last year.

Just what the latest threats of terror mean for those things will soon be seen.