Since the first covertly recorded tapes purportedly featuring opposition leader Kem Sokha talking to an alleged mistress emerged, questions have persisted about whether the CNRP acting president’s phone had been tapped.

Yesterday, a lawyer, acting for one of six charged with allegedly bribing 24-year-old Khom Chandaraty to stay quiet about the affair, lent credence to those concerns, alleging those investigating the case had obtained recordings that could only have been made through wiretapping, while a government spokesman said Sokha was being “monitored”.

“They questioned [my client] based on telephone communications to Adhoc officials who [my client] has been involved with [in the past] and is now charged alongside,” Sam Sokong, lawyer for former senior Adhoc official now National Election Committee member Ny Chakrya, told Voice of Democracy.

“This audio, we do now know where it is from, but [the prosecutor] said they have it. I have not seen or heard this evidence; I just know that they have it.”

In the two months since the first recordings were leaked to Facebook, the Anti-Corruption Unit and anti-terror police have used the tapes as the basis for a slew of legal cases that are widely considered politically motivated.

As of yesterday, Chakrya, four senior members of rights group Adhoc, an opposition commune chief and a UN human rights worker have been charged in relation to the scandal. Sokha and two CNRP lawmakers were also yesterday summoned to face court.

Reached yesterday, ACU president Om Yentieng did not directly respond to questions about whether his agency had tapped the phones of those it was investigating.

He instead said that he could not reveal his sources, before referring to an “insider” who, he claimed, had substantiated the allegations.

“If I eat rice do I have to inform you?” he said. “The law asks us to protect our sources . . . If we cannot protect the source, we would go to prison.”

Yentieng, however, also pointed to the ACU’s legal right to tap phones.

“We can tap whatever we want . . . but we only use it when necessary,” he said.

Article 27 of the Anti Corruption Law empowers the body to tap phones without approval by an investigating judge, as is typically required in the Criminal Code, if they get a “hint” that a corruption offence may have occurred.

Speaking yesterday, Council of Ministers spokesman Phay Siphan said that Sokha was being “monitored” after a complaint to the ACU, though refused to divulge any information beyond that.

He said Sokha qualified for surveillance as he held “extremist” views and had issued calls for violence in the past.

Though the ACU can tap phones, the Cambodian Code of Criminal Procedure, in Article 83, directs that investigators must maintain professional confidentiality, a breach of which is punishable under the Criminal Code.

As the first recordings were released on a Facebook page belonging to Chandaraty – which she said was hacked – a ruling party spokesman initially suggested she had recorded them herself.

Though as new tapes began appearing almost immediately on a Facebook account called “The Truth of CNRP”, officials largely avoided discussing their provenance.

Last week, days after the ACU arrested opposition commune chief Seang Chet for offering Chandaraty’s family cash, the same Facebook page posted a recording purportedly featuring the local official talking with Sokha about such a payment.

Soon after, Yentieng noted he had known for a “long time” about the recording.

Transparency International Cambodia executive director Preap Kol said that while Article 27 could be a “powerful tool” to fight corruption, it could be abused for political reasons if law enforcement agencies were biased and favoured certain political parties.

He called for greater oversight to protect the constitutional right to privacy.

Legal expert Sok Sam Oeun, meanwhile, said the ACU would eventually need to explain its evidence.

“If they [tapped phones] . . . they must have reasonable grounds to show the judge that the person was involved with corruption,” Sam Oeun said.