The U.K.’s National Crime Agency (NCA) announced on Wednesday that a man has been arrested in connection to the ransomware attack that disrupted several European airports over the weekend. The attack, targeting check-in systems provided by Collins Aerospace, caused delays at airports in Brussels, Berlin, Dublin, and London’s Heathrow. The arrested man, in his forties, was taken into custody in West Sussex under the Computer Misuse Act. While released on conditional bail, the investigation is ongoing, according to the NCA.

RTX, the owner of Collins Aerospace, confirmed in an SEC filing that the cyberattack involved ransomware, leading to flight delays and cancellations. The incident was first revealed by European cybersecurity agency ENISA and has impacted customer-specific networks. Despite the confirmation, details about the ransomware type and hackers responsible remain unclear. Technology journalists Lorenzo Franceschi-Bicchierai and Zack Whittaker, reporting for TechCrunch, are covering the ongoing investigation into the ransomware attack.