Emails sent to self-exiled former opposition leader Sam Rainsy, among others, were trotted out during the court’s questioning of Australian James Ricketson yesterday, though advocates questioned how the missives justified the “espionage” charges levelled at the 68-year-old filmmaker.

Ricketson was arrested in June last year after he flew a drone without a permit over an opposition rally. He was charged under espionage laws with gathering information for a foreign power that could damage national security, a charge he has repeatedly denied and which critics have dismissed as politically motivated.

Ricketson was questioned for two hours yesterday by a judge in a closed Phnom Penh Municipal Court session, and is expected to be questioned again next week, according to his lawyer, Peung Yok Hiep.

Yok Hiep said the judge focused on the content of three emails obtained from Ricketson’s seized computer. The emails were the first pieces of alleged evidence Ricketson has seen during his eight months of pre-trial detention.

In an email to Rainsy from 2013, Ricketson allegedly asks for confirmation as to whether Rainsy was subject to a new arrest warrant. At the time, Rainsy was head of the Cambodia National Rescue Party, which was forcibly dissolved in November following the September arrest of Rainsy’s successor, Kem Sokha, on widely decried accusations of “treason”.

Yok Hiep said Ricketson confirmed sending the email to Rainsy.

“It is normal, because he is a journalist, to meet politicians”, Yok Hiep said. “He just wanted to confirm with Sam Rainsy, but he was charged with collecting information.”

Rainsy said he was unable to locate the email in question yesterday, but he defended Ricketson, saying he was simply doing “his work as a journalist” in corresponding with him.

“Emails I received from him were of the kind I received from many other foreign journalists,” Rainsy said in an email. “Now James is only a scapegoat and a hostage held by the government to frighten other foreign journalists and deter them from writing critical reports about the Hun Sen regime.”

In another email, Ricketson allegedly responds to an email from a foreign friend inquiring about the number of bodyguards assigned to Prime Minister Hun Sen, and how many water cannon trucks – used to break up protests – the government had available. Yok Hiep did not disclose who sent the email, but said Ricketson responded by saying the number of bodyguards was about 10,000.

It is widely reported that Hun Sen’s bodyguards number is in the thousands. A paper from academic Lee Morgenbesser last year estimated the premier’s Bodyguard Unit counted some 3,000 members and, when combined with Brigade 70 – which shares a commander with the unit – and the elite 911 Paratrooper Brigade, the total number of effective bodyguards was roughly 9,500.

Adding in the 8,000 gendarmerie police the premier controls, his security detail is “a paramilitary architecture equivalent in size to the national militaries of Senegal, Somalia, or Zambia”, Morgenbesser wrote.

In a third email discussed yesterday, an Indian woman asked Ricketson to help a Cambodian film team with a project for an NGO, which Yok Hiep couldn’t immediately identify.

Australian press freedom advocate Peter Greste, a former Al Jazeera journalist who has advocated for Ricketson and was himself jailed in Egypt on widely condemned national security charges, said on the surface there was insufficient evidence to prove espionage.

“There is certainly not enough here to make a case for spying, and they look like pretty bog standard things for a journalist to ask,” he said in an email.

But, he stressed, “context is everything”. If the email requesting numbers came from a CIA agent, Ricketson’s case would be a hard one to argue, but supplying numbers already in the public domain hardly amounted to espionage, Greste said.

“A legitimate question by a journalist can, out of context, seem very much like seeking information as a spy,” he said, saying enquires about bodyguards could simultaneously come across as “suspicious and banal”.

Ricketson’s case has taken place against the backdrop of a broader pre-election crackdown on not only the opposition CNRP, but also on independent media outlets.

Two Radio Free Asia journalists have also been arrested on “espionage” charges in recent months after their outlet was forced to shutter its in-country operations. Meanwhile, dozens of radio frequencies carrying content from RFA and Voice of America were closed in the lead-up to the CNRP’s dissolution. The often critical English-language Cambodia Daily newspaper was forced to close around the same time after being hit with an “exorbitant” tax bill.

Kingsley Abbott, senior international legal adviser at the International Commission of Jurists (ICJ), noted that the law was being wielded by the ruling Cambodian People’s Party against critics, echoing an ICJ report last year that said rule of law was “virtually absent” in the Cambodian justice system.

“What we are continuing to observe into 2018 is the wilful weaponization of the law to silence dissent and dismantle representative democracy within the country – all under the stated pretext of implementing the ‘rule of law’,” he said in an email.

Ricketson is being held in the capital’s notoriously overcrowded Prey Sar prison, where he was recently moved to a cell containing 140 inmates.

His son, Jesse, was present at the court yesterday. His family has expressed concerns about Ricketson’s ongoing detention, due to his age and his health.

“He absolutely denies the charge against him. He’s baffled as to why this is all happening in the first place,” Jesse Ricketson said. “He acknowledges that he flew a drone and he acknowledges that he didn’t have a permit for flying the drone, but beyond that . . . [it] is a mystery to him and us.”

“They’re trying to see if there is any information in his emails that implicates him in spying for anyone. As it stands, there isn’t anything in those emails. Hopefully through that questioning they’ll realise that they haven’t actually got any evidence.”