The North Korean hacking group known as Kimsuky was found to be behind the distribution of a malicious email sent to foreign affairs and security experts in South Korea last year.

According to the Korean National Police Agency on Wednesday, the hacking group, a unit under the North’s Reconnaissance General Bureau, sent phishing emails to 150 such experts between April and July of last year.

The agency confirmed that nine of the recipients, including three former minister or vice-minister-level officials, had their account information stolen after clicking on a link in the malicious email.

The police said the organization, which was behind the 2014 hacking of the Korea Hydro and Nuclear Power Company, stole file attachments and directories from the victims but no confidential information was among the seized materials.

The group sent the phishing email after hacking into 36 servers in South Korea and 102 in other countries and laundering IP addresses.

The agency’s announcement comes five days after the government imposed unilateral sanctions on Kimsuky.