Hans-Christian Vadseth, a former newspaper editor and partner at Oslo lobbyists First House, spotted the theft when he realised that 12,000 kroner had been taken out of his account with a card he believed had been swallowed up by a bank machine.
When he checked his account online he realised that the gang running the machine had also made a number of purchases at Kondomeriet, a nearby sex shop.
"I discovered what had happened when I went into online banking and saw that someone had taken out money and made purchases on Kondomeriet," Vadseth told Norway's TV2.
"I must say that I am a bit shocked to experience something that you only read about. Everything seemed entirely plausible. The ATM gave me a receipt to say that the card had been swallowed."
A gang of four Romanians are on trial in Oslo for planting the card catcher in Oslo during the Christmas shopping rush last December, after being caught by surveillance cameras.
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"There is strong correlation between the card logs and the surveillance photos and massive photo evidence in this case," Tor Hamnes, the prosecutor, told a court in Oslo on Wednesday.
Three of the four men have previous convictions for crimes carried out in The Netherlands, England, France and Austria.