The Supreme Court recently ruled that files from a “spy app” for illegally recording voice files cannot be used as evidence of adultery as it violates a communications-related law.

In 2022, a woman sought compensation from her ex-husband’s mistress based on calls recorded between her ex-husband and his mistress as evidence. The woman collected the evidence using a spy app she had secretly installed on her husband’s phone.

Two lower courts admitted the evidence, ruling that the ex-husband should pay his ex-wife 10 million won ($7,400) in compensation.

However, the Supreme Court overturned the decision, ruling that the recorded files could not be used as evidence. The court stated that recording calls without the consent of both the caller and the receiver constitutes eavesdropping on electronic communications and thus violates the Protection of Communications Secrets Act. “The calls recorded by means of illegal eavesdropping do not have any evidentiary capacity.”

In 2019, the woman learned that her husband, who was a doctor, was having an affair with a woman he met at his hospital. However, the woman reportedly did not bring up the issue as she was also having an affair with another man.

The following year, when the husband discovered his wife’s affair, the couple divorced by mutual consent in 2021. In 2022, the wife filed a complaint seeking 33 million won in damages from her ex-husband’s mistress, and submitted files of recorded phone calls between her ex-husband and the woman as evidence.

The Supreme Court only accepted the fact of the ex-husband’s cheating based on other evidence and confirmed the previous ruling that he should pay 10 million won to his ex-wife in compensation.