According to Allkpop, on April 9, the Trubaum Research Center revealed the results of the Author Identification Assessment conducted with text messages that are believed to be conversations between actor Kim Soo Hyun and the late actor Kim Sae Ron via KakaoTalk in 2016, comparing them to text messages that Kim Soo Hyun sent to his acquaintances in 2025.
Kim Soo Hyun's side directly requested an assessment from Trubaum and provided document data from 2025.
According to the report, the Author Identification Assessment assesses statistics on whether the documents were written at different times and whether they were compiled by the same individual.
This method measures the number of times certain words appear in each document, calculating their average usage over 18 language characteristics. By identifying an individual's language model, evaluate and determine whether the messages were likely written by the same author.
Trubaum found that there was no significant statistical difference between Kim Soo Hyun and Kim Sae Ron in 2018 and model messages provided by Kim Soo Hyun, actual messages exchanged between him and acquaintances in 2025. The probability of those messages being written by the same individual (Kim Soo Hyun) is 92%.
However, the research firm found a statistically significant difference in language samples when comparing 2016 messages with 2025 messages. The assessment shows that there is a "high probability" (95%) that the 2016 messages were not written by Kim Soo Hyun.
Meanwhile, YouTube channel Garosero Research Institute and Kim Sae Ron's family previously released the recreated text messages between Kim Soo Hyun and Kim Sae Ron to prove that the two stars dated in 2016, when Kim Sae Ron was still a minor.
However, some have questioned the "reliability" of the restored text messages, forcing Kim Soo Hyun to hire a private company that specializes in appraising evidence in court to question their validity.
