North Korea reportedly launched cyber attacks against South Korea using the Itaewon crowd crush tragedy.

According to a report released by Google’s Threat Analysis Group on Thursday, hackers from North Korea known as APT37 sent out malicious documents disguised as press releases from the interior ministry about the tragic incident.

The report said the group discovered the vulnerability on October 31 after several people uploaded a Microsoft Office document to VirusTotal, a service that analyzes files for viruses.

APT37, also known by other names such as Red Eyes, previously conducted cyber espionage campaigns targeting North Korean activists in South Korea as well as officials in the defense ministry.