Police raided the SK C&C building in Seongnam, Gyeonggi Province on Friday, as part of an investigation into a fire at data centers in the building that caused a massive service disruption at Kakao and Naver.

Investigators from the Gyeonggi Bundang Police Station are seeking evidence that will help them determine whether abnormal signals were detected from servers prior to the fire that erupted last Saturday.

They will also seize documents on battery inspections, as well as fire and safety management, to determine the exact cause of the blaze that more than 100 firefighters put out in two hours and another six hours to ensure no sparks or embers remained.

The incident debilitated the nation's hyper-connected society as users were unable to access Kakao's mobile messenger KakaoTalk, online payment system Kakao Pay, Kakao Mobility taxi app and other services for more than 24 hours.