Danish police on Wednesday charged two journalists and a leading magazine publisher over alleged payments to a rogue IT expert in return for celebrity credit card data.
Police raided the journalists' homes and the offices of Aller Media, just over a week after charging a man for supplying gossip magazine Se og Hør with confidential information from an online payment company.
One of the men was Ken B. Rasmussen, a former journalist at Se og Hør who last month released a purportedly fictional book detailing how the magazine used private credit card information to write stories about members of the royal family.
Se og Hør scoops included Denmark's Prince Joachim's 2008 honeymoon in Canada, a story which baffled the tabloid competition at the time since it had been kept secret.
The credit card transactions of former Danish Prime Minister Lars Løkke Rasmussen were also said to have been monitored. Actor Mads Mikkelsen is among a handful of celebrities who have made allegations against Aller Media to the police.
Copenhagen police said it had searched the offices of Ken B. Rasmussen's book publisher but added that the company was not suspected of any wrongdoing.
In what has been dubbed "Denmark's biggest media scandal", observers have drawn parallels with Britain's News of the World, which was shut down by Rupert Murdoch in July 2011 following allegations of widespread phone hacking.
Police have said the man suspected of leaking the information initially worked at a firm now part of card payment company Nets, before the group outsourced his job to IBM.
The scandal has prompted tightened security measures at Nets, which in March was bought for $3.1 billion (2.3 billion euros) by US private equity houses Advent International and Bain Capital, and Danish pension fund ATP.
The group handles more than six billion card transactions per year.