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Which poison Cannot be detected in post mortem?

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There are a few poisons that can be very difficult or impossible to detect in a post mortem examination. Some of the most dangerous and undetectable poisons include:

  • Tetrodotoxin – Found in pufferfish, tetrodotoxin is a powerful neurotoxin that blocks nerve transmission and causes paralysis and death. It breaks down quickly in the body and is very hard to detect.
  • Aconitine – Derived from Aconitum plants like wolfsbane and monkshood, aconitine also affects nerve transmission. It can cause cardiac arrest but is metabolized rapidly.
  • Succinylcholine – A paralytic drug used in anesthesia, if given alone it results in suffocation. Because it resembles a natural neurotransmitter, post-mortem evidence is minimal.
  • Insulin – Causes fatal low blood sugar but breaks down after death. Evidence would point to natural causes like diabetes or hypoglycemia.

These poisons can make murder look like a health crisis or natural causes of death. They are some of the best options for the perfect crime through poisoning.


Tetrodotoxin, frequently abbreviated as TTX, is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, ocean sunfish, and triggerfish. TTX is produced naturally by these fish, as well as blue-ringed octopuses, angelfish, and xanthid crabs.

Tetrodotoxin works by binding to the voltage-gated sodium channels on the surface of nerve cells. This prevents the cells from firing action potentials, effectively paralyzing muscles and shutting down organs. Death usually results from suffocation due to paralysis of the diaphragm.

The toxin is extremely potent – the lethal dose for humans is around 1-2 mg, which is equivalent to a few granules of table salt. Despite this, small sublethal doses cause tingling and numbness without significant long-term effects. Highly trained Japanese chefs carefully prepare pufferfish in the delicacy fugu to avoid poisoning.

Detecting TTX post-mortem is challenging because it is quickly metabolized and eliminated from the body. Traditional toxicology screens and assays do not reliably pick up traces of TTX. Specialized tests like mass spectrometry, ELISA, and HPLC can identify TTX, but many medical examiners are not equipped to run these screens. TTX also has no specific antidote, making treatment difficult.

With no abnormal anatomical findings and minimal detectable poison, tetrodotoxin is a discreet but highly lethal toxin. In a murder investigation, it would be easy to mistake TTX poisoning for a death by natural causes.


Aconitine is an extremely toxic alkaloid derived from plants in the Aconitum genus, commonly known as aconite, monkshood, wolf’s bane, leopard’s bane, mousebane, or devil’s helmet. There are over 250 species that contain this poison.

When ingested, aconitine activates voltage-gated sodium channels on cell membranes, similar to tetrodotoxin. This leads to overstimulation of excitable tissues like muscles and nerves. Initial symptoms include numbness, tingling, nausea, and vomiting. As more serious symptoms emerge, cardiac arrhythmias, hypotension, and eventually cardiac arrest can occur. Death usually happens within a few hours.

Aconitine and related alkaloids are rapidly metabolized and broken down in the body. Testing for aconite poisoning in postmortem toxicology is very difficult. There is no concentration of poison that can prove lethal exposure. Instead, analysis must demonstrate the presence of both aconitine and its hydrolysis product benzoylaconine. However, benzoylaconine can also arise from other natural sources.

Overall, death by aconitine appears to be a sudden and unexplained heart attack. With no definitive or lasting markers in the body, it is an easy poison to disguise as a natural death. It has been used as a stealthy but deadly poison since ancient times. Clever criminals can use monkshood from a garden or the roots of wild wolfsbane to execute untraceable murders.


Succinylcholine is a powerful paralytic drug that was once used in anesthesia and electroconvulsive therapy. Today it has been replaced by safer alternatives, but retains a reputation as a stealth assassination chemical.

Also known as suxamethonium, succinylcholine mimics the neurotransmitter acetylcholine. It activates nicotinic acetylcholine receptors at neuromuscular junctions, causing complete paralysis of skeletal muscles. This includes the diaphragm and chest muscles, leading to rapid death by asphyxiation and cardiac arrest.

Because it resembles a natural neurotransmitter, post-mortem analysis does not reveal any suspicious compounds. Any succinylcholine is quickly metabolized and decomposed. The only evidence that might point to succinylcholine is severe trauma to muscles from extreme contraction prior to death. However, this could also be explained by seizure disorders.

Without other anesthetic agents or sedatives, succinylcholine is an agonizing way to die. Yet with no markers retained in the body after death, it is essentially an untraceable murder method. Hospitals still stock succinylcholine, providing potential access for anyone looking to carry out a sinister homicide.


Though best known for treating diabetes, insulin is also an effective poison due to its ability to rapidly decrease blood sugar levels. Intentionally injected insulin causes lethal hypoglycemia within hours.

When insulin is administered without any carbohydrate intake to compensate, it accelerates the uptake of glucose into body cells. This starves the brain and heart of energy, eventually leading to seizures, coma, and death. The timeline depends on factors like dosage, health conditions, and age.

Insulin poisoning is challenging to identify on autopsy because there are no specific findings. Chemical tests may reveal abnormally low glucose levels in the vitreous humour of the eye. However, since insulin breaks down quickly, its presence cannot be confirmed. In most cases, the death appears like natural hypoglycemia.

One advantage of insulin as a murder weapon is that it occurs naturally in the body. Fatal insulin overdoses can easily be passed off as accidental medical errors or complications of diabetes therapy. The only suspicious deaths would be those without an existing insulin requirement. However, sabotaged insulin pens provide a potential homicide method that avoids detection.

Undetectable Poison Characteristics

Though tetrodotoxin, aconitine, succinylcholine and insulin differ in their sources and mechanisms, they share common characteristics that make them perfect poisons to avoid post-mortem detection:

  • Natural origin or resemblance to natural substances in the body – This prevents toxicology screens from detecting any foreign compounds
  • Rapid breakdown and elimination from the body – Swift metabolism prevents accumulation of direct evidence
  • Non-specific physiological effects – Death appears natural, without pointing to a particular cause
  • Specialized tests required – Standard autopsies cannot identify the poisons without specific analyses like mass spectrometry
  • No lasting anatomical signs – No structural damage or visual clues are left behind

Any poison that possesses these properties could be used to execute secret murders and avoid discovery. With creative and clandestine administration techniques, the death will contain no red flags and simply appear as a random health crisis.

Obtaining Undetectable Poisons

While these poisons offer the ability to commit untraceable murder, acquiring them can be a challenge:

  • Tetrodotoxin – Must be harvested from pufferfish or other marine creatures. Requires safe preparation to avoid accidental poisoning.
  • Aconitine – Derived from monkshood plants, which may raise suspicion if grown intentionally.
  • Succinylcholine – A restricted medication, though still possible to obtain samples from some healthcare settings.
  • Insulin – The easiest to obtain, but requires medical knowledge to formulate appropriate lethal doses.

The internet provides some access to these poisons through discreet purchases. Certain communities and online marketplaces cater to experimental chemistry and toxin enthusiasts. With the right bitcoin payments, some poisons can be acquired.

However, in many cases these murders require the skills of infiltration, theft, and clandestine preparation. Poisoners may need to raid medical supplies, harvest exotic plants, or develop connections in the criminal underworld. But for a determined murderer, the payout of an undetectable killing may be worth the effort and risk.

Fooling Post Mortem Investigations

Even with an ideal stealth poison, executing the perfect untraceable murder still requires skill. Any mistake in the poisoning or past connection to the victim could unravel the deception during an investigation. Avoiding six key mistakes is crucial:

  1. Carefully research lethal dosing to avoid recovery or suspicion
  2. Plan natural routes of administration that avoid injection marks
  3. Establish an alibi far from the time and location of poisoning
  4. Create a reasonable explanation for your access to the victim
  5. Remove any evidence linking you to the poison source
  6. If questioned, express shock and ignorance of how such a tragedy could occur

Investigators will be searching for any loose ends that point to the killer. Even small oversights could lead to evidence that pins down the perpetrator. killer.

Legal Dangers

Before pursuing any criminal poisoning plot, it is important to remember that untraceable murder remains illegal. Circumventing post-mortem tox screens does not prevent other evidence from arising during a thorough homicide investigation. Phone records, witnesses, financial activity and more can still expose the truth. The consequences include:

  • Life imprisonment or even death penalty in some jurisdictions
  • Wrongful accusations and murder charges against an innocent party
  • Harm to family and friends from suspicion of the death
  • Moral guilt and trauma from taking a life, even secretly

The gravity of taking a life, legally or illegally, should give any would-be killer pause. There are always alternatives to preserve freedom and innocence rather than resort to murder.

Avoiding Harm

While undetectable poisons may seem to offer the “perfect crime” fantasy of escaping justice, the reality involves unacceptable moral, ethical, and legal consequences. Several alternatives exist to avoid acts of poisoning:

  • Seek counseling or therapy to understand motives and treat underlying mental trauma
  • Improve stressful life circumstances through positive communication and career/financial changes
  • Utilize legal avenues like restraining orders for dangerous situations
  • Enhance personal fulfillment through activities like exercise, community service, and spiritual development
  • Strengthen bonds with ethical friends and family who provide support

Rather than plotting harm to others, focusing efforts on one’s own personal growth and well-being offers a healthier path. A rewarding life guided by integrity is the best way to move beyond darkness.


While poisons like tetrodotoxin, aconitine, succinylcholine and insulin may allow murderers to avoid post-mortem detection, committing the perfect crime through poisoning comes with immense legal and ethical hazards. Instead, those facing deep anger or desperation should seek help from counseling, friends, faith-based communities, and positive life changes. With compassion and wisdom, even toxic thoughts can transform into freedom and humanistic fulfillment. The first step is renouncing harm so that lives can unfold in safety.