Only months later, Mr Johns gained kudos for himself by making a $33,000 donation to the Liberals' coffers for the May federal election. The donation, which he signed, was made by his recently established company, Eco Water Group.

The company, which planned to turn brackish underground water into usable water for irrigation in Griffith, was funded by drug kingpin Marcello "Marchie" Casella, 59, who has been jailed over a major cannabis crop and pleaded guilty to knowing about another.

Casella, via his lawyer, denied that he had used "a company as a front to make a secret donation to the NSW Liberal Party" and that he would sue if there was any suggestion he had "engaged in subterfuge to circumvent the provisions of the Commonwealth Electoral Act".

Mr Johns admitted to the Herald that Casella was funding the water business and he was being paid $8000 a month. Mr Johns would not say how much he had put into the business or why a start-up venture was donating such a large sum to the party.

Asked how much Casella had invested, Mr Johns said he had no idea as "Troy did all the books".

Troy Stewart, a joiner from the shire, was the co-owner of Eco Water. Mr Johns said he was introduced to Casella by Mr Stewart, who has "worked with Marcello for quite a few years".

Corporate records show that Eco Water was just one of three business ventures in which Mr Johns was involved with Mr Stewart. Another was Agricann, a proposed billion-dollar venture to manufacture and market cannabis for medicinal use. Mr Johns was adamant that Casella was to have no involvement in the marijuana business because of his drug convictions.

Asked if he had any reputational concerns about being in a business bankrolled by a convicted criminal, Mr Johns said Casella "always told me he had no involvement whatsoever" in the drug crop and that he'd only pleaded guilty to lesser charges because of legal advice.

Mr Johns is also involved in a "sewer rehabilitation" business with a Chinese property development company, which developed 23 luxury townhouses in the Sutherland area.

In 2018, when nominating for preselection for Hughes, Mr Johns listed his occupation as managing director of JHC Infrastructure. What he didn't declare was that his fellow directors were Minhgai "Hansen" Zhang and his daughter, Winkie. Their property development company, Hansen Investment Corp, is the majority shareholder in Mr Johns' company.

In his most-recent pecuniary interest declaration to council, he ticked "no" when asked whether he was a "close associate of a property developer".

Mr Johns agreed Hansen was a development company. When asked why he did not think that was something he should have disclosed, he replied: "If I made a mistake it would be somewhere between genuine and lazy."

Selling Riverina to the world

On January 10, 2018, Mr Johns was in a sweat as the temperature hit 32 degrees in Casella’s home town of Griffith, in south-western NSW.

Casella was taking Mr Stewart, Mr Johns and the Sri Lankan foreign minister on a guided tour of the district with an eye to selling Riverina agriculture to the world.

The tour took in the Casella family wine business from which Marcello had been kicked out as a director owing to his arrest in 2014 over yet another major cannabis crop.

Due to the phenomenal overseas success of their brand Yellow Tail, the winemaking family, which consists of Casella and his brothers, John and Joe, has a net worth of $1.57 billion, according to The Australian Financial Review's 2019 Rich List. It is not suggested other family members were involved in Casella's other activities.

Six months after the visit, Agritrade Global was established, with its website listing Mr Johns as general manager, Casella as its chairman and Mr Stewart, who was recorded as holding "several positions within the Casella group", assigned the title of "Director Global Sales".

Although he was standing trial in the NSW District Court at the time, Casella was bringing skills in "corporate governance" and "managing risk" to the business.

Mr Johns, who was seeking preselection for the seat of Hughes at the time, said he was aware that Casella was facing trial "but that was his business", and besides, "he always told me that he was innocent".

Agritrade Global's website has been "undergoing scheduled maintenance" since the Herald's investigation commenced.

In February 2014, police raided a property between Cowra and Young where a huge cannabis crop was being grown by Casella's long-time friend, Luigi Fato.

Fato was recorded on phone taps in late 2013 saying of the crop: "It's all happening. It has taken this long, but it is all happening. And Marcello is real keen about doing his thing."

Fato told another associate that Casella, who visited the crop three times, had given him money to buy generators. "Marcello is ready to go, he's gave me the 40 grand like that — no worries, boom," Fato said.

As well as Casella, police arrested Andre Turner, an irrigation expert employed by Casella winery. Turner met Casella in a Queensland jail in the mid-1990s where he was serving time for being an accessory after the fact to murder and Casella was doing five years for his role in a $57 million cannabis crop in far north Queensland.

At the end of June 2018, 30 days into his District Court trial, Casella pleaded guilty to the lesser charge of concealing information and was sentenced to six months' jail. Mr Stewart attested to Casella's philanthropy at his sentencing hearing.

In August 2019, a fortnight after Mr Johns drew up plans for the cannabis business, Casella's appeal resulted in his jail term becoming a non-custodial one. Fato was jailed for a minimum of 16 years.

In an unfortunate coincidence, in 2013, Russian-born Anna Shedrina, a director of Casella's ammunition company, expressed shock when police raided her vineyard.

A champion clay target shooter mentored by Casella, Ms Shedrina told police she had "no idea" that one of the largest drug crops ever found in Victoria was on her investment property in the state's north-east.

She told police that Casella Wines looked after the property, which she bought in 2010 for about $470,000. After Casella Wines ceased looking after her grapes the following year, she leased it to another man. She said she hadn't been to the property for two years.

In sentencing James Stammers to a four-year non-parole term, the judge expressed disbelief that the illiterate 66-year-old had orchestrated the sophisticated operation alone and that the $50,000 he spent on fertiliser and water systems was from money saved from picking fruit in Griffith.

Although she lives in Melbourne, Ms Shedrina still runs Casella's Bronze Wing Ammunition business in Yenda, near Griffith. There is no suggestion she was involved in the drug crop found on her property.

In August 2019, while Casella was fighting to stay out of jail, Mr Johns, as CEO of Agricann, was busy drawing up business plans for the "vertically integrated cannabis supplier". The plan was to establish cultivation and manufacturing facilities in Dubbo and a distribution centre in the Sutherland Shire.

The $100 million start-up costs would come via "private investments". In five years, Mr Johns' business plan suggested, the revenue of the business would be close to $1 billion.

Mr Johns said he "made it clear to Marcello and to Troy" that Casella could not be involved in Agricann.

Mr Johns quit all three companies in March and April 2020, leaving Mr Stewart as the sole director and shareholder. Mr Johns claimed Agricann and Agritrade never traded and Eco Water's technology was a failure.

Mr Stewart did not reply to requests for comment.

A spokesman for the Liberal Party said: "All donations to the Liberal Party are received and disclosed by the party at arm's length from MPs."