Such a low cost and simple methods for making bombs sends a "clear alarm for everyone that a terrorist can attack at any place at their desired time with their desired devastation," the report notes.

The report puts a maximum price tag of Tk 40 for all the materials used in each of the bombs, except for the detonator.

Aside from the detonators, all the parts of such a bomb are available in electrical spare shops. "The components are generally used to prepare various electric circuits or devices," the report points out.

The experts could not determine the country of origin of the detonators as it is not available in the local market.

But this type of detonator is used for military and commercial (oil exploration, mining) purposes. "The price of a similar type of military detonator is approximately Tk 55," the report says.

This means that the Jamaatul Mujahedin Bangladesh (JMB) needed to invest, at minimum, only around Tk 50,000 to make the approximately 500 bombs that simultaneously rocked 63 district headquarters on August 17.

"This investigation shows that a militant group does not need a lot of money to send a terror wave," an investigator comments to The Daily Star. "It's their determination, networking and planning that is the prime concern for us."

The report adds that a medium caliber expert on electric circuits prepared the time circuit.

"The connection pattern and pattern of equipment suggests that it was prepared at the same place and most likely a single individual connected the components, except the soldering iron part. The individual had good knowledge of the colour code of electric wires. In no case was the colour code violated, which indicates the individual's professionalism, skill and technical training in this regard. An expert can prepare around 50 complete circuits within 12 hours of a day.''

The experts also conclude that the explosives were probably intentionally made less harmful, possibly to avoid checking and detection by security forces. More harmful bombs would have increased the size of the explosives.

Due to the use of a small amount of gunpowder and homemade explosives, victims at very close proximity to the bombs sustained small but lethal splinter injuries and serious burn effects. People at a distance of more than three feet could have been safe from the blast.

The experts noted that the complete bomb was handed over to the carriers, keeping the battery pack disconnected from the circuit. It is assumed that an expert conducted a training or a briefing session at the district headquarters to train the carriers how to connect the battery pack with the circuit, start the delay time by switching the timer on and place the bomb at a desired place.

Last Wednesday night, law enforcers recovered a huge number of bombs, materials and detonators from JMB's den in the city's Goran area. According to experts, these bombs and their materials were identical to those used on August 17.