Police investigator Bent Isager-Nielsen said officers searched the homes of Ken B Rasmussen and Kasper Kopping, who used to work for Se og Hoer magazine, to find more evidence. They also raided the offices of a media group and a book publisher.
Rasmussen, who was laid off in 2012 as part of sweeping staff cuts, relates in a recently published book how reporters used information from a secret source at IBM with access to a card-payment company's computers.
Rasmussen said that the magazine had paid the informant 1,840 USD a month for the leaks, but declined to give more information about him.
He said their techniques were far superior to those used by reporters at the now-defunct British tabloid News of the World which was engulfed in a phone hacking scandal, describing those as "pure boy scout methods" in comparison.
He detailed how they were able to closely tail Prince Joachim, Queen Margrethe's second son, and his second wife, French-born Marie Cavallier, on their honeymoon, by using information about where and when the newlyweds used their credit cards.
The suspects face a maximum prison sentence of six years if found guilty, but have only been provisionally charged by the police, a step short of formal charges.
