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.
"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.