Opposition lawmaker Son Chhay last week sent a letter to Justice Minister Ang Vong Vathana seeking his ministry’s interpretation of the criminal procedures for “red-handed” crimes – a legal rationale used by the government to justify the arrest of Cambodia National Rescue Party President Kem Sokha in spite of his parliamentary immunity.

Kem Sokha was arrested earlier this month following the reappearance of a 2013 video showing him admitting to receiving US assistance to plan his political career. The remarks were construed by the government as collusion with a foreign power to harm the Kingdom, with Sokha summarily charged with treason.

Officials have justified the arrest as a “red-handed crime” – a nod to the constitutional clause allowing lawmakers’ arrest in cases of in flagrante delicto offences – because the video still exists online.

Chhay’s letter asks the justice minister to explain how Sokha’s and other arrested CNRP members’ crimes fit under the heading of in flagrante delicto, which refers to a crime in which the perpetrator is caught in the act.

“Therefore, the arrest of a National Assembly member, who has immunity, violates Article 86 of the Criminal Procedures Code because the reasoning for the accusations is baseless,” it reads.

Justice Ministry spokesman Chin Malin said they had yet to receive the letter and that Vong Vathana would decide whether to respond in person or through a letter of his own.