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Definition

•Any substance that causes injury or illness or death of a living organism

•Anything that harms or destroys

•Advantages:

–Stealth

–Separation from criminal to victim

–Difficulty identifying criminal who administered

–May be disguised as a natural cause of death

Who uses poison?

•Chemicals may be hard to come by:

–Only professionals who have access

–Doctors, Pharmacists, etc

•Accidental poisoning

–Mistakes of prescription medication

–Accidental ingestion of household chemicals

•Suicide

–Example: Normal medications taken in excess

Accidental Poisons

•Some chemicals are too easily detected to be used for murder

•These are usually found in accidental deaths

•Household Chemicals:

–Strong acids (ex. Battery Acid)

–Strong bases (ex. Drano)

•However some criminals still use acids to try to destroy evidence/body

Accidental Poisons

•Disinfectants

–Lysol

•Gardening Supplies

–Slug killing chemicals

•Carbon Monoxide

–By-product of incomplete combustion

–Replaces the oxygen in the blood

–Causing person to fall unconscious

Suicides

•Many suicides use prescription medications taken in excess

•Especially drugs that will knock person unconscious so that they don’t have too much pain:

–Choral hydrate

–ASA –used for anesthesiology

•CO piped in from a car exhaust

–Causes the person to fall unconscious

Identifying CO Poisoning

•Carbon Monoxide poisoning easily recognized

•Carboxy-hemoglobin in blood turns:

–Skin

–Internal organs

•Bright cherry red

•Evidence lasts even months after death

•If body is not found –cause of death can still be determined

Murderers’Poisons

Murderer wants the following:

•Poison to be lethal

•To happen at time or place that is separate from criminal activity

–Can have an alibi

•Produce symptoms that suggest a natural cause of death

•Not be traceable to the specific murderer

Natural Poisons

Hemlock

•Conium maculatum –known as Hemlock

•Symptoms look like suffocation

•Socrates’suicide

Aconitine

•Extracted from Monkshood

•Paralyzes the body’s organs

•Heart failure or lung failure

Atropine

•Extracted from nightshade

•Headaches to hallucinations

•Eventually coma

•Heart or respiratory failure

•Dilates the eyes:

–This is evidence of atropine poisoning

–Also used in very small doses for some eye treatments

Strychnine

•Extracted from Strychnos nux-vomica

•Extremely bitter tasting

•Violent muscle contractions

•Jaw paralysis renders victim speechless

–Muscles draw back into “grin”

•Death caused by paralysis of lungs

•Was mistaken for tetanus or epilepsy

Chemical Poisons

Thallium

•Metal salt

–Dissolves into water invisibly and tastelessly

•Symptoms look the same as:

–Muscle weakness, the flu or just old age

•Death by internal organ damage over time

•Victim’s hair will fall out

Antimony

•Elemental metal

•Symptoms look same as:

–Stomach sicknesses/infections

•Stomach pain, loss of appetite, painful cramps and diarrhea

•Eventually convulsions and heart failure

Cyanide

•Organic chemical:

–Carbon and Nitrogen

•Works the same as carbon monoxide

–Starving the blood of oxygen

•Works in a matter of minutes

–Much faster than CO

•Distinct almond smell and very bitter taste

Arsenic

•Elemental metal

•Symptoms similar to:

–Extreme food poisoning

–Cholera or Dysentery

•Headaches, confusion, convulsions

•Traces are evident in all body parts

–Even years after poison was administered

Medicinal Drugs

Morphine

•Derived from Opium

•Depresses the CNS –blocks pain

•Overdose may lead to respiratory failure

Heroin

•Also derived from Opium

•Overdose will lead to the heart stopping

Also –Codeine, Demerol, Vicoden

Depressants

Alcohol

•Relaxation, euphoria, drowsiness

•Alcohol Poisoning

–Confusion, Seizures, even death

•More commonly:

–Choke on vomit while passed out/asleep

Barbiturates/Tranquilizers

•Same symptoms and problems

Stimulants

Cocaine

•Stimulating the CNS

•Feelings of confidence, energy, excitement

•Give way to dread, paranoia and fatigue

•Death from heart failure

Amphetamines

•Same symptoms and problems

Forensic Tests

•Begin with a sample of victim’s blood, urine or tissue

•Screening tests:

–Check rapidly for wide variety of drugs or poisons

•Identify exact substance:

–Gas or liquid chromatography

–Immune based assays

–Mass spectrometry

Gas Chromatography (GC)

•Liquid sample is injected into machine and vaporized into a gas

•Sample travels through a column at different speeds depending on its size and chemical composition

•How long it takes to travel through column is noted:

–Each component is identified

•Exact chemical can be identified by its different components

Liquid Chromatography (HPLC)

•Liquid sample is placed onto a gel or film

•Solvents are added to see how different components of sample will move through gel/film with different solvents

•Examine each component’s banding pattern on gel/film:

–Each component is identified

•Exact chemical can be identified by its different components

Immuno-assays

•Using an antibody that is raised against that specific drug/chemical compound

•Raise antibodies in an animal model

–Administering drug/compound to animal

•Then add antibodies to test sample:

–Either of pure drug

–Or of blood, urine or tissue

•If antibodies react then drug is present

•VERY specific test

Mass Spectrometry

•Every compound has a very specific pattern on a Mass Spec

•Put compound into Mass Spec

•Bombard with stream of electrons

•Component will break up and produce a very specific pattern of light

•Every known drug/poison/atom/chemical has a known mass spec pattern

Drug Identification

•If drugs are found at the scene

•Can be tested and identified quickly

•Glass tubes with treated crystals that will react to specific illegal drugs

•Add a small sample of the drug in question and watch for specific reaction/color change in the tube

•Sort of similar to a breathalyzer for alcohol

–Only done on the drug not the person