The desktop in question was in the Christchurch offices of Westpac, a leading New Zealand bank. At its keyboard sat a woman with 30 years' experience who was about to perform a routine task: formalising an overdraft facility. The account was that of Mr Gao, 29, who ran a filling station in Rotorua, a tourist town on North Island.
The bank had agreed to give him a NZ$100,000 (£39,000) lifeline, and the woman was entering the amount on a loan clearance form. Every digit, including the two zeroes for the cents, was put in. But one thing wasn't: the decimal point. And its absence gave Mr Gao and friend not $100,000, but 100 times that amount. Suddenly, the couple who had been heading towards insolvency had $10m, and a lot of temptation, in the bank.
Westpac did not at first spot the error – a supervisor missed it – but soon after the money was transferred on Monday 5 May, Leo Gao did notice. But then, to a man used to seeing the letters OD all over his bank statements, the sudden replacement of them with a bottom-line credit in eight figures would rather catch the eye. If he was fleetingly inclined to call the bank and tell them of their mistake, the feeling soon passed.
Instead, he began to make hasty plans to take the money and run. He and Kara told friends they were about to go "on holiday"; and, unlike other couples who have hit the road after similar accidental windfalls, they invited the family to join them. Several declined, but Mr Gao's mother and her sister, Aroha Hurring, agreed to drop everything and come along for the ride.
Kara's seven-year-old daughter Leena naturally came too, and Mr Gao's business partner, Huan Di Zhang, also decided to do a flit. That decimal point was changing quite a few lives.
To say they left in a hurry is something of an understatement. Mr Gao closed the petrol station (bequeathing a shock to the few regular customers, and its sole employee, Shybu Antony); left Sam, his and Kara's border collie, tied up by the kennel in the backyard of their three-bedroom home; and headed for Auckland, three hours' drive away.
There was no time to clean out their car and when the white Holden Commodore utility vehicle was found at Auckland airport, sitting forlornly in Row B of the long-term car park, the back seats were covered in a dirty duvet, a bag of Pedigree dog biscuits, a rusty handsaw and waste paper. The windscreen displayed a Warrant of Fitness that expired three months ago.
They were ticketed through to Hong Kong, and had landed and cleared the usual channels before Westpac realised their error. By 7 May, the Gao party were thousands of miles away from the bank and New Zealand police, on the territory of other jurisdictions altogether, and now in with a serious chance of getting away with it.
Maybe it was the euphoria, but they didn't fancy a period of restraint, anonymity and self-control. They moved on to Macau, and started spending like there was no tomorrow, which, in their case, was a plausible assumption. There were reports they'd hit the tables of local casinos, and Westpac, who seem to know more than they have so far divulged, last week named Wynn Resorts, which owns a Macau casino, in a lawsuit seeking to recover the lost millions. And Kara's sister Aroha changed her Facebook status to read: "Aroha Hurring is having a Tsingtao beer. It's 30 degrees plus – the heat is good though."
Meanwhile, back in New Zealand, the filling station had a notice on the window saying it was in receivership, and deliveries of milk and newspapers began to build up outside its locked doors. Grateful locals helped themselves.
Westpac hired a private detective, Mike Dingwall, and the first that some of Mr Gao's connections knew of what he'd done was when Mr Dingwall turned up on their doorstep, brandishing photographs of the absconders, and asking questions. Few people had any significant answers. Probably even more frustrating for the bank is the continued absence of their money. Of the NZ$10m (£3.9m) overdraft, Mr Gao tried to transfer $6.7m; $2.9m was swiftly recovered, leaving him with $3.8m (£1.48m).
Finally, on 20 May, the media was let in on the secret, and the story made the proverbial headlines around the world. And, while the Gaos were still apparently jollying away some of their misgotten gains, the publicity winkled out some tentative information about them and their lives in New Zealand.
Whatever his origins (some reports had him as a Chinese national, others a Korean), Mr Gao seems to have long been fixated on the idea of becoming rich. Acquaintances described a man who, as a wheeler-dealer, was rather better at the wheeling than the dealing. The Rotorua filling station he bought had turned out, in the words of a neighbouring business owner Peter Davis, to be "a bit of a lemon". (He and Mr Zhang had been trying to sell it for nearly a year.) And Mr Gao's attempts to expand his fly-blown business empire stumbled a little more when he bought a fish-and-chip shop opposite the garage, failed to make a go of it, and had to sell it at a loss.
He had also moved, with what seems to have been an unerring instinct for a bum deal, into the buy-to-let market. He owned at least one property in Auckland, an old wooden house where tenants shared a bathroom and kitchen, and got the impression that Mr Gao had other property. These houses are presumed to have been heavily mortgaged, rather like his own home, upon which he still owes $245,000. He had recently tried to sell the place for less than the amount he borrowed. All in all, his story has echoes of John Darwin, the multiply-mortgaged British canoeist who faked his own death and skedaddled to Panama – another man whose feeling of entitlement led him to dip his fingers in life's till.
Back across the Indian Ocean, the party had begun to break up. Aroha Hurring headed for home, and has now been interviewed by police as a witness. She said the errant couple were no longer together. Ms Yang (nee Hurring, aka Young, or Yang-Hurring – she appears to have nearly as many surnames as her man has mortgages) was still in Hong Kong, while Mr Gao had left, possibly for the mainland.
With his nationality, appearance and mother in tow, finding him among China's population of 1,330,044,544 will be something of a challenge; especially as the Chinese police are not, more than three weeks after he absconded, formally looking for him. Interpol, not noted for its strong presence in Beijing, is said to be involved, and a New Zealand officer has reportedly flown there to try to find the couple. The investigation has now reached the stage where police are issuing appeals to the couple to return home, invariably a sign that they have run out of promising leads.
These days, when taking money off a bank is regarded not so much as a crime as a service to the community, Mr Gao has his admirers. Hundreds have signed up to three Facebook groups, including one with an authentically Down-Under title: "Go Leo Gao – Go You Good Thing".
But this is not an entirely victimless caper. A family has been divided by greed, poor father of three Mr Antony has lost his job at the filling station, tenants don't know if they'll still have a home, and, back in Christchurch, the woman who forgot the decimal point is undergoing trauma counselling. Meanwhile, somewhere in Asia, the spending goes on.