‘Physics and chemical lab’ of Burdwan

KINSUK BASU, TT, Calcutta, Oct. 26: The ammunition, weapon parts and chemicals found at the October 2 blast site have prompted forensic analysts to dub the Burdwan home a “combined physics and chemistry laboratory” probably focused on mass killings.

The Telegraph spoke to officials from the Central Forensic Science Laboratory, Calcutta, and other analysts to understand the nature of the seized material.

Till early last week, the scientists had only a partial idea. “We’ll carry out further examinations of the seized items to ascertain the terror module’s ammunition-producing capabilities,” CFSL director Priyankar Ghosh said last week.

The following is information collated from multiple sources, some of whom cautioned that the analysis was a dynamic process and definite conclusions were yet to be reached.

PHYSICS LABORATORY

Home-made 8mm bullets

Made with metal and plastic tubes, they feature brass heads and small fan-like blades to ensure a longer trajectory.

Surprise element: Home-made guns have been seen in Bengal before but never home-made bullets, which are more difficult to make.

“This is an uncommon bullet shape. The small blades have been fitted strategically at the point where the bullet’s head meets the body,” a scientist said.

Lighter than ordinary bullets (made of lead heads and brass base filled with gunpowder), these bullets need the blades to cover any sizeable distance, ballistics veterans said.

Questions: Who gave them the technology? How did they acquire the knowledge and expertise?

Another question is how the suspects or the eventual users intended to fire the bullets. Some officials spoke about the possibility of “spraying” the bullets from launchers — many at a time to offset the lack of accuracy.

But an army veteran was cautious, saying grenades —which cover an area — could be lobbed from launchers but he was not sure whether bullets, largely used to strike individual targets, could be fired in a similar manner.

“We are still in the process of ascertaining which mechanical device would have been used to fire the bullets,” a forensic official said.

Timer watches

Fitted to bombs, these small watches ensure that a pin goes off at a designated time, causing an explosion.

Surprise element: Ordinary timers work within a time frame of 12 to 24 hours but those found in Khagragarh can theoretically be set up to cause an explosion much later. A forensic official said such timers were seen several years ago at a blast site in Jammu’s Maulana Azad Stadium.

Questions: How did these watches reach Khagragarh? What sort of delayed explosion was planned?

Launcher designs, lathe machine

The suspects had downloaded from the Internet designs of launchers capable of firing grenades. A lathe machine was found. So were a few launcher components such as “aerodynamic cover” and “conical liner”. The two components are usually used in “shaped charges” — called so since the cavity is “shaped” in a manner that focuses the impact of the explosive’s energy.

It is not clear yet what the Burdwan module intended to do with the lathe machine and the components.

Irregular and guerrilla forces abroad have been known to rig up hand-held or shoulder-launched grenade launchers using similar components. Originally used by the Soviets, such launchers are popular among insurgents because they can be made at low cost and without drawing much attention. In 1993, two US Black Hawk helicopters were downed in Mogadishu by a Somalian militia using shoulder-launched grenades.

Surprise element: The manufacturing process is relatively simple but understanding the design of a launcher requires a certain proficiency in physics. Calculations in projectile motion are involved in building a launcher — if indeed the Burdwan module was trying to make a launcher.

Questions: If a launcher was in the works, where did the suspects receive the training and from whom? Also, which target or targets were they planning to take down?

CHEMISTRY LABORATORY

Chemicals and equipment

As many as 33 kinds of chemicals, as well as lab equipment, were found. “The flat looked like an R&D centre, with so many types of branded chemicals stored in two cupboards,” a forensic official said.

Stockpiling so many chemicals at one place — some inflammable and some highly poisonous — is extremely risky even for trained handlers.

Surprise element: The compounds included potassium chlorate, sodium azide and picric acid, none of which can be bought without official clearances and certificates.

Potassium chlorate

Used in safety matches and explosive devices. “Chlorates are a favourite with terrorists because they release high energy in ionised form during chemical reactions,” a forensic scientist said. Two years ago, India banned the use of potassium chlorate in fireworks (added for extra colour and height), as practised in China.

Sodium azide

Turns explosive at 300°C or in contact with certain metals. It’s a severe poison like cyanides — can be fatal in contact with skin or if swallowed. Mixed with water or acid, it changes into a toxic gas.

Picric acid

A yellow crystalline solid used in explosives.

Potassium nitrate

Used in fertilisers, rocket propellants, fireworks and gunpowder.

Ammonium nitrate

A white crystalline solid used as fertiliser and in mining explosives, as well as terrorist bombs.

Others

The scientists are trying to figure out what some of the other 28 chemicals were meant for. They include sodium chloride (common salt), ethanol (drinking alcohol), methanol and the highly corrosive nitric acid and sulphuric acid.

Questions: How and from where were these chemicals procured? Some go into explosives but what were the rest meant for? Were chemical weapons being planned?