It was confirmed that the alleged KakaoTalk conversation, surrounding the youngest member of BIGBANG, Seungri (29, Lee Seung-hyun), was submitted to the police in the form of an Excel file stored inremovable storage device (USB ).

The police said the file do contain the contents of the alleged December 2015 conversation that revealed the sex service activity. However, if you do not get the original text of the conversation, the prospect that the contents of the conversation written in the Excel file is not easy to prove the crime. It is because it is hard to exclude the possibility of arbitrary creation or manipulation. 

Lee Sang-jin, a professor of information security at Korea University, said, "It is difficult for legal documents to be displayed only with the excel files that have been exchanged. There is no way but to recover the contents of the conversation by securing a smartphone or computer hard disk that exchanged messages with KakaoTalk. "

 An official of the broad investigation department said, "It is difficult to prove the criminal charges of the people who talked with only the KakaoTalk conversation. After analyzing the data, we will review the summons. " 

edit: basically, even after confirming the chat even exist, they then need to confirm it was in fact Seungri (and the others who alleged involved) who send those messages. Until then, an Excel file of electronic messages/conversation is not a irrefutable & concrete evidence.