This month 43-year-old Iranian-born Australian Mohammad Dashti walked into an Artarmon storage unit housing several pallets of fruit juice boxes.

Waiting police were more interested in the fact the juice containers allegedly hid 47.5 kilograms of ''black tar'' heroin, along with almost 2.2 kilograms of brown heroin and 25.5 kilograms of ice - all up worth more than $26 million on the streets.

The alleged discovery of the ''black tar'', a processed opium known as a cruder form of heroin, sourced from Afghanistan, has stunned police.

''In 25 years policing I've never seen black tar heroin before,'' said Detective Inspector Jon Beard, of the Organised Crime Squad.

Even more surprised was Mr Dashti - he wet himself when the raid was carried out.

''He was pretty shocked when we turned up. It was a full evacuation, you could say,'' a police officer involved in the operation told The Sun-Herald.

Police allege Mr Dashti is the principal of a syndicate importing drugs from Iran, in particular the unprecedented amount of black tar. The Drug Squad commander, Detective Superintendent Nick Bingham, said black tar was smoked rather than injected.

''It is less refined but popular among the Iranian and Muslim community due to a cultural reluctance to inject heroin,'' he said.

The investigation into this emerging drug trend spread to Western Australia, where a storage unit at Perth Airport was raided a day after the Artarmon bust. Similar juice boxes, 78 in total, are being chemically analysed and are believed to contain black tar heroin.

Mr Dashti faces possible life sentences given the significant amount of drugs. He has been charged with two counts of commercial supply of a large quantity of drugs, been refused bail and will reappear in court on March 29.

Police have since investigated Mr Dashti's connections in the tight-knit Iranian community, based predominantly in western Sydney.

Detectives searched a number of homes, examined financial records and a food importation business at Glendenning called Ausie Foods, run by Iranian-born Akbar Jeyranpour. Police and customs interviewed Mr Jeyranpour and searched the Ausie Foods premises before taking the office computer. But Mr Jeyranpour was shocked by the police attention.

''It's impossible we are involved,'' he said when contacted by The Sun-Herald. ''This is complete news to us all. I have run Ausie Foods for 18 years. If I was a drug dealer

I would have 10 houses, not rent my current house.''

Mr Jeyranpour said he had never met Mr Dashti, although he knew his brother. ''The brother has a shop in Canberra, sometimes he buys goods from me.''

Mr Jeyranpour said police had focused on the food importation business because Abbas Bayatpour - the husband of an Ausie Foods director, Naghmeh Fard Kermanshahi - had unwittingly leased the Artarmon storage unit to Mr Dashti.

''They used to have another shop and used the storage space for their products. He did not change the lease and let Dashti use it. I don't know why or how they know Dashti,'' he said.

Mr Bayatpour has come to the attention of authorities before.

In December 2003, Supreme Court Justice Peter Hidden fined him $1.396 million for his role in smuggling illegal tobacco.

The Sun-Herald was unable to contact either Ms Kermanshahi or Mr Bayatpour. It is understood they live in Sydney and police have confiscated their mobile phones.

Iranian organised crime is firmly on the radar of Australia's top crime-fighting body. The Australian Crime Commission reported last year the country's ''political instability'' was ripe for abuse.

Police have been investigating several Iranian-run remittance payment services that operate like Western Union, transferring cash between countries.

Last November The Sun-Herald revealed two men had been jailed for an elaborate money laundering scam that involved $95 million being sent from Parramatta's Little Persia convenience shop to Tehran.

Do you know more?

igridneff@sunherald.com.au