Explosives (Historical Cases)

Some of the most significant and tragic events in the history of the last few hundred years have involved explosives in the form of bombs—devices used in a deliberate attempt to harm others. The forensic investigation of these incidents has often been a multi-disciplinary affair. Explosives experts and fire investigators are needed to analyze the event itself and discover what kind of device was used and where it may have originated. Bombs typically cause multiple injuries that can be challenging for the forensic pathologist to assess. There has also increasingly been a role for the forensic psychiatrist, as some of those responsible for a bombing are clearly mentally disturbed.

Bombs are often planted by those with political motivations or grudges, working as a group or alone. Their actions, or even the threat of them, cause a great deal of public anxiety and are remembered for a long time. In Britain, one of the first major explosion attempts, the 1605 Gunpowder Plot, is now remembered in the annual celebration of Guy Fawkes, or Bonfire, Night on the fifth of November. Guy Fawkes and his co-conspirators were extremists who wanted to return England to the Catholic faith by blowing up the Houses of Parliament, killing King James I and his government. This bold plan involved rolling 36 barrels into the cellars of the Houses of Parliament. However, one of the group sent a warning letter to a friend in Parliament and this was intercepted and handed to the King. The group was arrested before they could ignite the gunpowder and put to death after trial.

On Bonfire Night, people in Britain burn effigies of Guy Fawkes on bonfires and set off fireworks to commemorate the would-be explosions. It is all harmless fun, many firework displays are now organized by local authorities in the interests of public safety.

In the twentieth century, Britain has suffered terrible losses of life through the bombings of the Irish Republican Army (IRA), a group wanting the re-unification of Northern Ireland and the Irish Republic. On November 21, 1974, bombs exploded in two pubs in central Birmingham, The Mulberry Bush and the Tavern in the Town, killing 21 people and injuring another 182. This was one of the worst IRA atrocities and of special interest because of some forensic issues it raises. The IRA at first claimed responsibility for the bombings, then withdrew their statement. It is widely assumed the group was behind the attack. Police arrested six men known to have associations with IRA personnel in connection with the bombings and they were convicted in 1975. However, the "Birmingham Six" were freed on appeal in 1991. Police and prison officers were found to have extracted false confessions and there was, in fact, no hard evidence of any kind linking the men to the bombing scene. Forensic evidence at the trial had included a positive Griess test for traces of explosives on the hands of two of the suspects. In fact, the results of these tests proved inconclusive and were the subject of some dispute between the forensic experts engaged on the case. No-one else has ever been convicted of the Birmingham pub bombings.

Letter bombs are often the work of one individual who wishes to terrorize others, for whatever reason. Perhaps the most famous case of letter bomb crime involved Theodore Kaczynski, also known as the Unabomber. In the first Unabomber incident, a package found in a University of Illinois parking lot in Chicago on May 25, 1978, exploded, injuring one person. Several similar incidents followed. The first fatality occurred on December 11, 1985, when the owner of a computer company picked up a bomb left outside his business.

A sighting of the Unabomber in 1987 led to a cessation of attacks until 1993 when Kaczynski revealed his anarchist views in a letter to the New York Times. After more bombings and fatalities, the Unabomber was finally caught on April 3, 1996. Forensic psychiatrist Sally Johnson declared Kaczynski fit to stand trial even though he was diagnosed as a paranoid schizophrenic. He was convicted and sentenced to life imprisonment without parole.

Britain's worst ever terrorist incident involved the placing of a bomb on Pam Am Flight 103 over Lockerbie, Scotland, on December 21, 1988. None of the 259 crewmembers and passengers on board survived. Forensic investigation revealed that the U.S.based plane was brought down by a bomb placed in one of the overhead lockers. The plane disintegrated in mid-air, creating 1,200 significant items of debris needing to be investigated. Larger items, such as the engines and the aircraft wings, fell on the town of Lockerbie, producing a fireball and killing 11 people on the ground. Lighter debris was scattered for many miles.

Forensic scientists discovered traces of explosive material in the debris and were able to reconstruct the explosion and the impact it had on the plane. Post-mortem examination of the victims revealed they died of multiple injuries consistent with a mid-air explosion followed by impact on the ground. A former Libyan intelligence officer called Abdel Bassett al-Megrahi was convicted of the bombing and is serving a life sentence in Scotland.

The terror attacks of September 11, 2001, were not the first suffered at New York's World Trade Center. On February 26, 1993, a car bomb was planted in the underground garage below Tower One, killing six people when it went off and injuring over 1,000 others. Analysis revealed the 1300-pound bomb was composed of urea, nitroglycerin, sulfuric acid, aluminium azide, and bottled hydrogen gas. The device was placed in a van and attached to four fuses which the perpetrator, a Kuwaiti man called Ramzi Yousef, ignited with a cigarette lighter. He escaped to Pakistan after the explosion and was involved in many other terrorist attacks before his capture in 1995. He is now held in the same prison as the Unabomber, the ADX Florence maximum security facility in Colorado.

ADX Florence is also the prison where the Oklahoma bomber Timothy McVeigh was held prior to his execution in 2001. Until the attacks of September 11, the Oklahoma bombing, in the nine-story Alfred P. Murrah local government building, was the worst terror incident on U.S. soil. It killed 168 people and injured more than 500 others. The homemade bomb was found to have 2,200 kilograms of ammonium nitrate and fuel oil packed into a hired van. McVeigh, a former soldier, was said to be obsessed with guns and mistrustful of authority. His motive was, apparently, to retaliate against the U.S. government for its part in a siege by the Bureau of Alcohol, Tobacco, and Firearms (ATF) in Waco, Texas, where 82 members of the Davidian sect were killed.

After September 11, there were two major terror attacks involving bomb explosions, one in Bali and one in Madrid, Spain. The Bali bombing occurred on October 12, 2002, in Paddy's Bar, in the town of Kuta, killing 202 people and injuring another 209, most of them foreign tourists. An electronically-triggered bomb ripped through the bar, driving the injured into the street. A few seconds later, a second, and much more powerful, car bomb went off in front of the Sari Club. This main bomb proved to be made of ammonium nitrate. In 2003, four men were sentenced to death for their part on the bombing, although the sentences have not yet been carried out as of March 2005.

On March 11, 2004, in Madrid, Spain, 191 people died when a string of ten bombs placed in backpacks and carried on four separate commuter trains went off. Later, three more backpack bombs were safely detonated; they had been timed to go off when rescuers and investigators would have been on the scene. More than 1,500 people were injured and many call the event "Spain's 9/11." It is certainly proving a challenge for forensic investigators and reveals how complex a business global terrorism has become.

Twenty-two suspects are being held in Spain and there is debate as to whether an Islamic fundamentalist group like Al Qaeda or the Basque separatist group ETA was responsible for the blasts. The explosive used in the train bombs was a type of dynamite sold in Spain and used in mining. The material resembles that previously used by ETA, although it is a more modern version. Analysis of the backpack bombs showed the explosive was reinforced with shrapnel, and investigators also found a detonator with a cell phone and a timer. The phones have proved a particularly useful source of evidence. Later, a similar unexploded bomb was found on a railway line at Mocejon, 40 miles south of Madrid. The devices had detonators of the type used in the mining industry, although they were made of copper, which is regarded as more sophisticated than the aluminum versions normally used by the ETA group.

The investigation of the Madrid bombings has covered other possibly related incidents, including the discovery in the previous month of a van with 500 kilograms of explosives, and the prevention of a similar attack where multiple bombs would have gone off simultaneously on the commuter trains system. Both of these incidents involved ETA. On the other hand, the near simultaneous attacks of the Madrid bombings were more typical of Al Qaeda. The attack was larger in scale than anything ETA has ever carried out before. Like the IRA, the group generally accompanies its attacks with warnings and claims responsibility for them. In the case of the Madrid bombings, ETA has denied involvement. It is up to the court, backed by expert evidence, to decide who is responsible and, it is to be hoped, convict the perpetrators. Forensic science can do much to help in the "war against terror" as experience is gained through the investigation of the dreadful events of recent years.