The trial of the alleged Australian spy James Ricketson ended on Wednesday with an additional charge of treason requested by prosecutors and Judge Seng Leang, who reserves the verdict of the Cambodian court until Friday.
He faces up to 10 years in prison if convicted of espionage and endangers the national defense.
In the final arguments, prosecutor Seang Sok said that Ricketson had entered Cambodia to incite hatred, with the aim of overthrowing Hun Sen and his government and providing information to foreign states that was detrimental to the country.
He also said Ricketson, 69, had used his filming as a cover story since 1995 for his espionage activities, citing a dozen emails used to justify the allegations.
"He has to take responsibility before the law with respect to his own illegal activities," he said.
He did not mention any country that Ricketson supposedly spied on, but he sought the additional charge of treason, which Judge Seng Leang said he would consider.
However, Ricketson said that the prosecutor had not presented any witnesses as required by the Cambodian law and that his arrest without a warrant was illegal.
He added that the notion that he was a spy and communicated Cambodian security issues to then-Australian Prime Minister Malcolm Turnbull through a Gmail account was "extravagant and ridiculous."
His defense argued that the evidence did not support the charge and that it was a mistake to imprison a man who had brought "culture and humanity" to the poor of Cambodia.
"James has done a lot of good here, nothing to do with espionage," said lawyer Kong Sam Oun in reference to his charity work. "It's impossible to be a spy for 22 years."
He said Ricketson's work as a journalist and filmmaker was legitimate, and that he has a right to his personal political beliefs, which "did not make him a spy."
The trial ended after his third week and follows 14 months of detention, an ordeal that began after Ricketson blew up a drone at a political rally organized by the opposition Cambodian National Rescue Party (CNRP).
The court has heard how Ricketson favored the CNRP over the ruling CPP in the elections before and after 2013, and that he had offered his services to the now ex-exiled leader Sam Rainsy.
The CNRP was dissolved by the courts after he was accused of trying to organize a "color revolution" to overthrow the Hun Sen government led by CPP.