In May 2019, Customs audited Clarke's importation business, reviewing the legitimacy of 25 imports over seven years.
Only two of the transactions, it found, were above board.
Six months later, Customs officers descended on the firm's Kaikorai premises, as well as Clarke's homes in Mosgiel and Cromwell.
They seized a "significant" number of documents - a paper trail that clearly exposed the fraud the defendant perpetrated.
Some of the importation forms had words and values obscured by white-out marker and others had small strips of paper glued on to hide the original value of the goods.
Of the 201 import entries associated with the company, 74 were doctored.
The prosecution summary of facts clarified Clarke's modus operandi.
He would undervalue the imported machinery by altering the invoices.
Those altered documents would then be forwarded to a broker, who then unwittingly submitted them to generate an official import entry.
That would then automatically calculate the Customs duty owing, which - due to the fraud - was lower than it should have been.
Across his various companies, Clarke employed more than 25 people, court documents said.
After pleading guilty, Judge Peter Rollo remanded the defendant on bail until his sentencing in July.
He ordered a Probation report, which would assess the possibility of Clarke serving an electronically monitored sentence.
The charge of altering documents carries a maximum penalty of 10 years' imprisonment.
