Al Jazeera had tracked down friends and family members of the man suspected of killing Kem Ley, Oeut Ang.
In a speech on Friday, Hun Sen argued that wire tapping was carried out across the world, including by the U.S. And European governments.
Thailand’s seafood industry has supplied the global market with about $7 billion dollars annually.
Prior to her arrest, Vanny had been regularly taking part in the so-called Black Monday protests, a campaign former to call for the release of several human rights workers and an election official jailed on corruption-related charges.
Tammy Davis-Charles, the co-founder of Fertility Solutions PGD, was detained along with two Cambodians, Penh Rithy, 28, a commerce ministry official, and a nurse, Samrithchan Chariya, 35.
The two witnesses in court on Wednesday claimed not to recognize the accused.
The protesters said they have faced numerous difficulties since being forced to relocate.
Kim Sok was charged with incitement and sent to pre-trial detention on February 17 after being questioned by the court of first instance.
On Wednesday, the authorities released security camera footage which appeared to show the suspect fleeing the scene of the crime.
Union leaders say the fall is due to legal roadblocks to workers registering complaints with the country’s arbitration body.
Last year, the government rescued 85 girls from many countries, including China, according to Mu Sochua.
During Thursday’s hearing, protests took place outside the court, leading four protesters to be badly beaten by district security forces.