Molecules of Murder

Criminal Molecules and Classic Cases

John Emsley

• Publisher: Royal Society of Chemistry
• Year: 2015
• ISBN:
  9781782627999
• Edition: 1
• Topic: History
• Subtopic: Science History
• Index: History

Molecules of Murder is about infamous murderers and famous victims; about people like Harold Shipman, Alexander Litvinenko, Adelaide Bartlett, and Georgi Markov. Few books on poisons analyse these crimes from the viewpoint of the poison itself, doing so throws a new light on how the murders or attempted murders were carried out and ultimately how the perpetrators were uncovered and brought to justice. Part I includes molecules which occur naturally and were originally used by doctors before becoming notorious as murder weapons. Part II deals with unnatural molecules, mainly man-made, and they too have been dangerously misused in famous crimes. The book ends with the most famous poisoning case in recent years, that of Alexander Litvinenko and his death from polonium chloride. The first half of each chapter starts by looking at the target molecule itself, its discovery, its history, its chemistry, its use in medicine, its toxicology, and its effects on the human body. The second half then investigates a famous murder case and reveals the modus operandi of the poisoner and how some were caught, some are still at large, and some literally got away with murder. Molecules of Murder will explain how forensic chemists have developed cunning ways to detect minute traces of dangerous substances, and explain why some of these poisons, which appear so life-threatening, are now being researched as possible life-savers. Award winning science writer John Emsley has assembled another group of true crime and chemistry stories to rival those of his highly acclaimed Elements of Murder.

Part I:
From Medicine to Murder

CHAPTER 1

Ricin and the Rolled Umbrella

A word shown in bold indicates that further information will be found in the Glossary

1.1 Waterloo Sunset

An umbrella is not the most obvious way of delivering a fatal dose of poison, but that was the weapon chosen by the Bulgarian secret service in 1978. Its targets were 26-year-old Vladimir Kostov and 49-year-old Georgi Markov, dissidents who had defected to the West and were embarrassing the corrupt communist dictatorship of President Todor Zhivkov by broadcasting on the US propaganda station Radio Free Europe. Kostov survived, but Markov died.

On 7 September 1978 Markov parked his car near Waterloo Station and was waiting for a bus to take him over the River Thames to Bush House, where he worked for the BBC World Service. Suddenly he felt a sharp pain in his leg, and turned to find a man behind him with an umbrella which he had dropped on to the pavement. Although Markov did not know it, the umbrella had fired a tiny metal pellet no bigger than a pin-head into his thigh. By the time Markov reached his home in Balham that evening he was already feeling very ill. He began vomiting and was running a high fever.

Markov was unaware that beneath the skin of his leg was a minute pellet containing one of the deadliest of all poisons. He died in agony four days later despite being in intensive care. The following week I was drawn into the story, when I was rung up by The Guardian newspaper to be told about the pellet that had killed him. Could I speculate about the type of toxic chemical which it might have contained? I guessed a spider or snake venom, but I was wrong. It was something far more deadly, and originating from a plant; it was almost certainly ricin.

1.2 Toxicology and Chemistry

Ricin is produced by the castor bean plant, Ricinus communis. It makes this toxic protein molecule in its seeds, presumably to deter predators. Once the seed has germinated the toxin is no longer needed and it disappears. Until this happens the ricin is indeed a very effective deterrent, deadlier even than the most powerful of the nerve gases. The toxicity of a poison can be judged by its LD₅₀. For ricin it is 0.1 micrograms per kilogram (μg/kg) of body weight, whereas the figure for the most lethal nerve gas known, coded VX, is as high as 20 μg/kg. Although these measurements were made using rodents, if they were to apply to a human they would suggest that for someone of average weight, say 70 kg, a dose of a mere 7 μg of ricin would pose a serious threat to life. This is a conservative estimate, as the route of exposure and the person’s immune status would also play a role.

The ricin molecule consists of two long chains, A and B, neither of which in itself constitutes a dangerous toxin—indeed other plants such as barley make chain A, without a noticeable effect on those who eat it. Chain B is the key to the toxicity. This binds to a particular carbohydrate component on the outside of a cell membrane and lies in wait. Eventually the membrane allows chain A to pass through, but once inside the cell it seeks out the site where the essential enzymes the cell needs are made and blocks it. Without its supply of enzymes the cell dies. A single ricin molecule is sufficient to kill a living cell, so in theory a mere 3 μg of ricin, with its ten trillion molecules, would be enough to poison every cell of the human body.

It has been estimated that it would take about 10 castor beans to kill a human, and the same is true for other domestic animals. On the other hand, hens and ducks seem to be relatively unaffected when they eat this number of crushed seeds, in fact it takes ten times as many beans to kill them, and one bird, the tambourine dove, happily consumes the seeds of the castor plant without harm. Humans are particularly sensitive to the toxin, and it has been said that a single bean contains enough ricin to kill a young child, although this is an extremely rare event, and certainly in the UK it is almost unknown for a child to be poisoned by swallowing a castor bean. Even when this has happened, the child invariably survives the ordeal. What protects a child from the toxin is the seed coating of the castor bean, which is so hard that provided it remains unbroken it can pass through the intestine undigested and emerge intact.

The fatal dose of ricin for an adult is calculated to be as little as 70 μg, ten times the amount estimated from its LD₅₀. In practice a higher dose than this is needed to kill, because the immune system begins to produce antibodies which destroy the ricin invader, and it also depends on the route by which ricin has entered the body, e.g. whether by injection, digestion or inhalation. In fact between 200 and 500 μg of ricin is needed to kill an adult, but this is still a minute amount and several such doses would fit on the head of a pin. A larger dose is needed to kill if the ricin is swallowed rather than inhaled or injected.

1.3 Ricin in Chemical Warfare

There is no antidote for ricin, but there are vaccines available to people who are likely to encounter the toxin. These have been developed because ricin has potential as a chemical warfare agent, and indeed may have been used as such in the Iran–Iraq war of the 1980s. That the Iraqis possessed this capability was confirmed in 1995 when they admitted to UN inspectors that 10 litres of concentrated ricin solution had been produced. They also admitted that it had been tested as an offensive weapon in the form of artillery shells which would explode and disperse it. There was also evidence that they had continued to stockpile ricin, and in 1998 the RAF and USAF attacked a castor oil production plant in Fallujah, Iraq, which was suspected of producing it. That there was a continuing threat from ricin seemed to be confirmed when quantities of it were found in al-Qaeda caves in Afghanistan.

It had been known for many years that ricin could be a possible weapon and work on it by the US Army began in World War I. Eventually they concluded that it offered no advantages over the traditional chemical warfare agents, chlorine and mustard gas, which were then in use. Nevertheless it was developed further in World War II when cluster bomblets were tested as a way of dispersing a cloud of ricin dust over an enemy, but again the conclusion was reached that it was not very effective. The dust was meant to contaminate clothing and surroundings so that even after the attack it would be possible for a person to ingest a fatal dose merely by breathing it in. It would remain a threat for quite some time until the bond between chains A and B was severed by chemical reaction with components of the atmosphere, such as ozone and nitrogen dioxide. Once A and B become separate entities then the potency is lost. The difficulties with ricin as a weapon were, firstly, the need to protect one’s own troops from exposure to it and, secondly, the inability to treat them if ever this happened.

Today, protection against ricin is possible but it has to be given before exposure to the toxin, in other words as a vaccine. There is still no antidote, nor is there ever likely to be. In 2003 the defence division of the US company, BioPharma, was licensed in the USA to test a genetically modified vaccine incorporating chain B, which induces the body’s immune system to produce antibodies against the whole ricin molecule.

1.4 Production and Applications

Ricin is produced naturally by a number of plants but in such tiny amounts that it poses no threat, whereas the castor plant makes it in relative abundance. This plant is grown as a crop for its oil, which is extracted by heating the beans to 140 °C for around 20 minutes to denature the ricin proteins, and then crushing and pressing the beans to extract the 50% or so of oil which they contain. More than a million tonnes of castor oil are produced every year, mainly from beans grown in Brazil, India and China. Castor oil consists almost wholly of just one relatively rare fatty acid, ricinoleic acid. Indeed the presence of this fatty acid in a blend of edible oils can be used to detect whether any castor oil is present. Castor oil is used for preserving wood and leather, and as a raw material for the production of sebacic acid, which is used in brake fluids and as an engineering oil.

In ancient times castor oil was burned in lamps or applied as an ointment to the skin. It was used in these ways in India as long ago as 2000 BC, and its laxative properties were also recognised. A spoonful of castor oil was prescribed as a cure for stubborn constipation, which it did indeed cure. This was partly due to the traces of ricin which it contained, but at a cost to the patient in terms of stomach cramps and gripes—indeed it could lead to severe diarrhoea and dehydration. For this reason it was used as a punishment in Nazi concentration camps, where prisoners would be forced to drink a cup of the liquid and suffer accordingly, sometimes dying as a result.

Ricin can be made from the waste left after castor beans have been cold pressed but it is a complex process involving a number of chemicals. It was first extracted from this source in 1888 by Hermann Stillmark and he named it ricin after the plant’s botanical name, which itself was derived from the Latin word for a tick, ricinus, because of the supposed resemblance of the seeds to these insects. A process for producing ricin was even patented by the US Army in 1962, although the patent was removed from public view in 2004 because it showed those of evil intent just how easy it was to produce the toxin using simple chemical reagents such as sulfuric acid.

1.5 Ricin Poisoning

The effects of ricin poisoning depend on whether it is inhaled, ingested or injected, but by whichever route it enters the body many organs will be affected. Initial symptoms of ricin poisoning begin to appear after around six hours. After inhaling a deadly dose, breathing becomes difficult and is accompanied by high temperature, coughing, and tightness in the chest. As fluid builds up in the lungs breathing becomes more and more difficult and the skin takes on a bluish pallor as the blood becomes deoxygenated. Death will eventually ensue. If a toxic dose of ricin has been swallowed then the person will eventually vomit and suffer diarrhoea and there will be signs of internal bleeding. The patient will experience severe dehydration and reduced blood pressure, and within a day or two of exposure, the liver, spleen and kidneys will stop working. If the ricin has been injected, death will be even quicker and could take place within 36 to 72 hours of exposure, depending on the dose. If the dose is truly minute and the victim has been able to survive for five days, then recovery is likely.

Because no antidote exists for ricin, the most important factor is to avoid ricin exposure in the first place. If exposure to ricin dust has occurred, the affected person should remove all their clothing and shower as quickly as possible, and then seek medical help. If it is known that some ricin has been absorbed, then the victim needs supportive medical care to minimise its toxic effects. He or she will need help with breathing and be given intravenous fluids to counter dehydration, together with medication to treat symptoms such as seizure and low blood pressure. If the ricin has been ingested recently, then pumping and washing of the stomach should be carried out using a slurry of activated charcoal.

1.6 Detection and Identification

The symptoms of ricin poisoning are often mistaken for other diseases and proper diagnosis can thus be delayed for several days. By this time it may be too late to save the victim. If it is known that the patient has been exposed to the toxin, then diagnosis can be confirmed quickly. The presence of ricin in contaminated materials can be positively identified using enzymes, and simple testing kits are available to do this. The US Environmental Protection Agency (EPA) established the Environmental Technology Verification Program to help with their development and to verify that they worked. A typical device is the AbraTox kit produced by the Advanced Monitoring Systems Center, employing the bioluminescent bacterium Vibrio fischer, which as its name implies emits light. When it encounters toxins in a sample of water the light emitted is diminished in direct proportion to the amount of toxin present, and it can detect as little as 15 ppm of ricin. (It will similarly detect nicotine, Botulinus toxin, cyanide, nerve gases and V-agents.)

Another detection method relies on strips that change colour. A sample of suspected water is applied to one end of the strip and as it diffuses along the strip it passes several stripes which have been impregnated with specific antibodies, labelled with coloured dyes. If they change colour they not only show that a toxin is present but identify which one it is. In some test kits the antibodies are labelled with fluorescent markers which reveal a change when exposed to light. BioThreat Alert is one such product and it can detect ricin at 50 ppm or less. (It is able to detect Botulinus toxin as low as 10 ppb.) A range of such sensors and test kits is now available, some much more sophisticated than others and costing as much as $20 000, and most will reveal the presence of ricin within 15 minutes. On the other hand the cost of simple test strips is relatively low. For example, there are strips that cost as little as $250 for 10 and which can detect ricin at 20 ppm. Even more sophisticated technology using fibre-optic biosensors is now available and relies on a fluorescent-labelled anti-ricin antibody, IgG, immobilised on the surface of the fibre. As it encounters ricin molecules it transmits the variation in light intensity back to instruments for a more detailed assessment. It does this with no loss of intensity, which is in any case faint, and slight changes of which are normally difficult to measure accurately.

Thanks to all these developments the idea of using ricin to contaminate a water supply is no longer a serious threat, since a ricin alert can be triggered automatically. This was not the case back in the 1970s when the KGB investigated it as an assassination weapon. Detection in those days was still extremely difficult.

1.7 Positive Factors

Ricin is not all bad,—indeed it may one day help to heal rather then kill. Research has shown that it may have some beneficial medical uses, possibly to kill cancer cells. Chain A of ricin linked to antibodies has been researched as a possible way of achieving this. In one example antibodies have been designed so that they are attracted to cancer cells, where they destroy the blood vessels on which the cells rely and so cause the cancer to wither away. Such immunotoxins have been shown to work in the laboratory, but have yet to be tested on living things.

1.8 Examples of Ricin Attacks

Dissemination of ricin as a dust via the mail system is one way to use it to attack people. This has been tried, but has so far proved unsuccessful.

Someone in the USA, as yet unidentified, posted three letters containing powdered ricin, the first in October 2003, the second in November 2003, and the third in February 2004. In the first of these the ricin was in a sealed container inside a package sent to Greenville, South Carolina, the second was in a letter addressed to the White House, and the third in a letter to a leading senator’s office in Washington DC. It was the last of these which caused the most alarm—the FBI kept knowledge of the first two out of the media. The third letter, addressed to Republican Senator Bill Frist, arrived on 2 February 2004 when he was Senate Majority Leader. As it passed through a mail-opening machine some white powder fell out but for some time went unnoticed. When it was observed, its discovery immediately suggested a repetition of the anthrax scare of 2001 when spores of this pathogen were disseminated as a powder via the US mail.

This ricin story began on 15 October 2003 when a package addressed to the Department of Transportation was intercepted at the sorting office which served the Greenville–Spartanburg airport, South Carolina. The package was labelled with a warning which read:

Caution RICIN POISON enclosed . . . do not open without proper protection

Inside was a small vial and a note signed ‘Fallen Angel’ which appeared to be from the owner of a fleet of tankers. Whoever it was, they demanded that new federal regulations reducing the hours which long-distance truck drivers could work should be withdrawn. If this did not happen by January 2004, when they were due to come into force, then Fallen Angel threatened to send more ricin-laden letters through the post. Inside the package was a sealed container and in it was a white powder which tested positive for ricin, but it was of such poor quality it really posed a threat to no one. Federal agents tried to discover the sender by accessing the drivers’ logs and time sheets of nine trucking companies who made deliveries in the Greenville area but nothing came of their investigations.

The next ricin-laced letter was addressed to the White House and had been opened at an offsite mail processing facility, where all such mail is subject to irradiation in order to destroy any possible pathogens. This safety procedure was instituted after the anthrax attack on various media organisations in the autumn of 2001, when letters containing anthrax spores were sent to Boca Raton in Florida, to New York City, and to the offices of two senators in Washington. These attacks killed five people and the nationwide alert disrupted the US postal service for several weeks. The person responsible was never found, or at least was never brought to court.

The second ricin letter arrived on 6 November and also contained impure ricin, with a note which threatened more attacks:

I will turn D.C. into a ghost town. The powder in the letter is RICIN. Have a nice day, Fallen Angel.

This letter was not made public until after the third ricin letter was received three months later. This third letter resulted in three Senate office buildings being closed down for a week, of which the one most affected was the Dirksen Senate Office Building, where the substance was found on the afternoon of Monday 2 February by a young worker in Senator Frist’s fourth-floor mailroom. Suspicion that this was another anthrax attack meant that 16 staff from that floor were immediately quarantined and decontamination was undertaken. Health officials urged other staff to report immediately if the...