In his first full statement since being arrested one month ago, jailed opposition leader Kem Sokha yesterday rejected any suggestions that he engaged in collusion with a foreign power against the Cambodian government, and called the midnight raid on his house a violation of his right to privacy and his parliamentary immunity.

The opposition leader was arrested on charges of “treason” on September 3 after a video shot in 2013 resurfaced the day before in which Sokha described getting American assistance to plan political strategies. Sokha’s letter yesterday was drafted by the party using notes handed over by his defence team, according to one of his lawyers, Sam Sokong.

In the three-page letter, Sokha accuses local authorities of violating his rights by breaking into his home and arresting him for allegedly committing an in flagrante delicto offence – or “red-handed crime” – allowing them to bypass his parliamentary immunity. He also denies that he committed treason – an accusation that has been parroted by senior government officials, including Prime Minister Hun Sen.

“On the point that the authorities charged me, of colluding or conspiring and working with foreigners to topple the government, it is completely slanderous,” he said. The jailed leader goes on to explain that, in a democracy, it is the job of the primary opposition party to replace the ruling party – a point he made in the video that precipitated his arrest – but maintains that he has attempted to do this in only a “peaceful and positive” way.

“If the opposition party does not attempt to replace the ruling party it cannot be called an opposition party,” the letter reads. “So all my actions are not illegal.”

“If our nation dies there will be no rich or powerful people. It means everything is gone.”

Sokha also appeals to the Cambodian people to continue their pursuit for justice and change – which he says is only half-finished – and also calls on the international community to act immediately to prevent a “useless” election in 2018.

“[The] international community often says that democracy in Cambodia is heading towards a dangerous [point], and now democracy is taking its last breath,” he writes.

CNRP Deputy President Mu Sochua and Sokha’s cabinet chief, Muth Chantha, both confirmed the authenticity of the letter, but directed further queries to his lawyers.

Sokong said the defence team had been taking notes since they first met Sokha at Tbong Khmum Provincial Prison, and he instructed them yesterday on which sections to include in the letter.

“We take notes, and he tells us what he wants to be in the letter. He wants to illustrate he is innocent and the authorities violated his rights,” Sokong said.

The government and law enforcement have been accused of violating parliamentary immunity in the past, which is only allowed in cases of an “in flagrante delicto” offence.

Even in such cases, the Constitution requires a two-thirds majority to lift an arrested lawmaker’s immunity. Though the ruling Cambodian People Party does not hold such a majority, it has repeatedly allowed cases against opposition lawmakers to proceed.

National Police spokesman Kirth Chantharith took umbrage with Sokha’s claims that the arrest was a violation of his rights, saying the CNRP leader was “wrong”, and that the police would not “dare” arrest him had he not committed a flagrant offence.

“We take action according to the law because everybody knows, and we also know, that he has immunity. That is a right that no one can abuse, except that he committed a red handed crime,” Chantharith said.