Experts have issued an urgent warning about a terrifying new psychoactive drug dubbed 'kush', after a former cabin crew member was accused of smuggling £1.5 million worth of the deadly drug into Sri Lanka.
Charlotte May Lee, 21, from Coulsdon, south London, was detained at Colombo airport on Monday, after arriving on a flight from Bangkok.
According to sources, authorities seized 46kg of kush as Miss Lee arrived from Thailand on a Sri Lankan Airlines flight.
Kush is a highly potent strain of cannabis.
It's made by spraying leaves with a mixture containing synthetic cannabinoids, formaldehyde, fentanyl.
According to some reports, the drug even contains ground-down human bones.
Since 2022, an even more dangerous form of kush has emerged, containing synthetic opioids called nitazenes, which can be 25 times more powerful than fentanyl.
Smoking the toxic drug produces euphoria, confusion, and sleepiness - often causing users to fall over and hit their heads on hard surfaces or wander into traffic.
What is kush?
Dr Kars de Bruijne, senior research fellow at the Clingendael Institute and author of a report on kush, told MailOnline that there are two forms of kush on the market.
Both start with a base of plant matter, such as marshmallow leaf, which is then sprayed with one of two psychoactive chemical mixtures.
Some forms of Kush are sprayed with synthetic cannabinoids, chemicals designed to mimic the natural psychoactive compounds found in the cannabis plant.
The synthetic chemicals are many times more powerful than even the strongest cannabis strains and can often have severe harmful side effects.
The second, more recent form of kush is sprayed with a mixture of synthetic opioids called nitazenes.
Dr de Bruijne says: 'It's an opioid so it's similar to heroin, but it's very strong and it's deadly because even a little more than a milligram too much is able to kill someone.
'What we've seen in Sierra Leone is that it is overdoses which kill.'
In a report for the Global Initiative against Transnational Organized Crime, Dr de Bruijne found that 50 per cent of kush samples tested in the lab contained nitazenes.
However, as kush moves through the market, it is cut and adulterated with numerous other chemicals, including formaldehyde, the painkiller tramadol, and even rat poison.
Most infamously, there are numerous unsubstantiated reports that kush contains human bones.
Although Dr de Bruijne's testing wasn't designed to detect human bone, he says: 'Everyone we spoke to that is a bit more serious in that market says they don't make it using human bones.'
Dr de Bruijne suggests that the rumor originated from the fact that early forms of kush used the synthetic cannabinoid ADB, a greyish-white powder with the street name 'bone'.
Combined with the fact that kush is sprayed with formaldehyde, which is used by mortuaries to preserve bodies, it is easy to see how the rum our began.
However, some are concerned that these rumors may have some basis in reality in a few fringe cases.
'I've also been speaking to people in the judicial system, and they have said that there is an increase in cemeteries where graves have been opened,' Dr de Bruijne explained.
'I think in Sierra Leone it happens more often that rumor turns into a reality.
However, the spike in grave robbing might be better explained by addicts searching for valuables to sell and, as yet, there have been no confirmed cases of body parts in kush.
What does kush do to your body?
Since kush can contain so many different chemicals, the effects on your body can vary widely.
In terms of its psychoactive effects, synthetic cannabinoids produce a response similar to that of cannabis, including relaxation and altered states of consciousness.
Nitazenes, meanwhile, trigger an intense state of euphoria and relaxation as well as nausea, vomiting, and fever symptoms.
Users also describe the high as being accompanied by a pounding pressure in the head and joints.
Over long periods of use, the drug causes swelling of the legs and feet, leading to sores and wounds which can become infected.
However, it is not currently clear why the drug has this effect.
Why is kush so dangerous?
Kush is a particularly dangerous drug because, once produced and sold, it is almost impossible to know what it contains.
At any point in the supply chain, distributors might have added unknown amounts of chemicals that could cause adverse reactions.
But the biggest risk is posed by the addition of nitazenes, which are both extremely strong and highly addictive.
Dr de Bruijne says that dealers call kush 'fast cash' because of how rapidly users become addicted and ramp up their consumption.
In Sierra Leone, an individual joint may cost as little as five leones (20 UK pence), but users can smoke up to 30 per day.
That is an enormous expense in a country where the average income is just £500 per year, often driving users into a life of crime to fund their habit.
Nitazenes also create a serious risk of overdose due to their potency, with experts warning that the drug has killed thousands of people in West Africa already.
Last year, a group of toxicologists from Imperial College, London warned that nitazenes were leading to a 'sharp rise' in overdose deaths in the UK.
Where is kush made?
According to the Global Initiative against Transnational Organized Crime, the kush found in West Africa comes from two locations.
Either the raw ingredients are imported from China and mixed in-country, or pre-made kush is imported from Europe.
From the European side, Dr de Bruijne says that the UK and the Netherlands have emerged as leading exporters.
'I've been speaking to people in that market to serious levels; they all pointed to the UK as the area of origin,' says Dr de Bruijne.
'When you speak to people in the port in Sierra Leone, they often point to or mention the UK.'
However, it's not yet clear whether the kush is being manufactured in the UK or simply moved through the country from another location.
Dr de Bruijne suggests that production lines are changing rapidly since the Taliban seized Afghanistan and destroyed the country's opium poppy trade, a precursor for producing heroin.
'The global supply of heroin is going down; the estimate from law enforcement is that the big cartels are preparing for a situation with less heroin and trying to find alternatives in synthetic opioids,' he explained.
Was Charlotte May Lee allegedly smuggling 'kush'?
Ms Lee was detained in Colombo on Monday after arriving on a flight from Bangkok.
Authorities accuse her of attempting to smuggle 46kg of 'kush' into the country.
Currently, the form of 'kush' containing nitazenes is an almost exclusively West African drug.
Although nitazenes themselves are found increasingly throughout Europe, the specific mixed form is much less common.
This makes it less certain which form of kush Charlotte May Lee is accused of smuggling.
Lucia Bird, director of the Global Initiative against Transnational Organized Crime's West Africa Observatory, told MailOnline: 'Key is to note that "kush" is a street name in Sierra Leone and elsewhere.
'Consequently, it is difficult to know whether something seized that is called "kush" is necessarily the same drug from the perspective of chemical composition if no chemical testing has been carried out.'
Ms Bird suggests that the drug in question was more likely to be cannabis and that the smuggling route is not tied to West Africa.
However, Ms Bird says that, if chemical testing does confirm the presence of nitazenes, it would be an 'indication of additional global spread of nitazenes, including in what were previously synthetic cannabinoid supply chains.'
Current reports suggest that kush typically arrives in Africa from Europe.
The UK and the Netherlands appear to be the most common origin points of pre-made kush.
This does not mean that kush is made in the UK, but it is, at least, a key point in the supply chain.
It is not clear where the nitazenes in kush are being produced.
Groups in Africa will also buy precursor compounds, such as synthetic cannabinoids, directly from China to make kush in the country.