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.
Annual report says civic groups in region “relentlessly threatened” amid rights set-backs over past year.
Russian lawmakers recently voted to decriminalize domestic violence in cases when there is no bodily harm. VOA Khmer's Seourn Vathana narrates.
Freedom Park had been closed since January 4, 2014, after the authorities destroyed the opposition’s protest camp.
The killing took place at a gas station owned by Caltex, a subsidiary of the California-based oil giant Chevron.
An outspoken government critic and popular grassroots activist, Kem Ley was gunned down last year on the morning of July 10 at a Caltex gas station in central Phnom Penh.